Salamanders & Newts :
Freshwater Aquarium Salamanders & Newts :
What is the difference between a newt and a salamander?
Newts are a subgroup of salamanders, so all newts are salamanders. As for how they're referred to, that can change depending on where you are. What is called a newt in North America may be called a salamander in Europe. The main differences are:
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Newts generally spend more of their adult life in the water or are fully aquatic, though there are exceptions to this.
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Newts are classified within the following genera - Cynops, Echinotriton, Euproctus, Neurergus, Notophthalmus, Pachytriton, Paramesotriton, Pleurodeles, Taricha, Triturus, and Tylototriton.
Salamanders and newts belong to the order Caudata, which includes amphibians that have, among other characteristics, a tail, a long cylindrical body, and limbs that extend at right angles to the body.
Courtesy to : www.drsfostersmith.com
-What do newts and salamanders look like?
The exact size and coloration vary by species, but they are all similar in that they have long bodies with long tails and soft skin that must remain moist. These amphibians have no scales, claws, or external ear openings.
- How long do salamanders and newts live?
The life span of salamanders and newts can exceed twenty years if they are cared for properly, so purchasing one as a pet brings with it a very long commitment.
-Are salamanders and newts poisonous?
Some do secrete toxic substances that can irritate human mucous membranes, and they can be highly toxic to other species of amphibians.
-Can I hold my salamander or newt?
We highly recommend that you limit handling your salamander or newt to when it is absolutely necessary, such as when you must clean the enclosure or inspect it for injury. Not only can the substances they secrete irritate our skin, but the oils on our skin are toxic to them as well. Additionally, the heat from our hands is dangerous for them. If you must handle your newt, wash your hands thoroughly before and after touching them, and handle them for as short a time as possible.
-What do salamanders and newts eat?
They are carnivores, and most will require a diet of insects and small invertebrates. This includes mealworms, pillbugs, earthworms, small millipedes, crickets, and brine shrimp. Larger adult species may also eat frogs, fish, or other salamanders.
-How should I feed them?
Salamanders and newts should be fed daily. They respond to motion, so most will prefer live prey over killed prey. They should only be fed as much as they will eat at one time, and any uneaten food should be removed immediately. Speak to your veterinarian about how much food your newt or salamander will need in one sitting.
-How big of an enclosure will my salamander or newt need?
The minimum tank size you should consider is 10 gallons. This will allow you to create the proper setup and temperature gradient and will give your herp enough living space. Keep in mind that if you are housing more than one salamander or newt, you will need to provide a larger habitat.
- What kind of habitat will my salamander or newt need?
There are three main kinds of habitats:
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Aquatic - for caudates that live their entire life cycle in the water
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Semi-aquatic - for caudates that live on land, hibernate during the winter, and go into the water to breed
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Terrestrial, some of which are arboreal - for caudates that live their entire life cycle on land, but live near water
To determine which type of habitat your newt or salamander will need, research the species and talk to your veterinarian.
- What do I need in an aquatic habitat?
Start with substrate - use washed gravel about 2" high on one side that slopes up to about 3" high on the other. Place live or artificial plants throughout the habitat for hiding places. You can also place smooth rock formations in the habitat as well, but be sure to leave lots of room for swimming.
- What do I need in a semi-aquatic habitat?
Start by splitting the habitat with a piece of glass or Plexiglass fixed to the sides of the tank with aquarium solvent. One side will be your land area, the other your water area. The size of each will depend on the species - some caudates need a 1/2 and 1/2 split, while others will only need a small land or water area, such as 1/4 of the enclosure. Put approximately 1" of aquarium gravel or coarse sand in the water area, then place water plants in it.
On the land side, your substrate should be made up of two or three layers. On the bottom, put down 1" of aquarium gravel or coarse sand, then put down sterile potting soil, peat moss, or garden loam. On top of that, you may want to put clumps of moss to help retain moisture and maintain humidity. For accessories in the land area, create plenty of hiding spots from pieces of bark, smooth rocks, artificial rock formations, potted plants, and pieces of terracotta pots.
Be sure to use a very tight fitting lid to prevent escape, and use substrate to slope the land area down into the water area to give your salamander or newt an easy way to get in and out of the water.
-What do I need in a terrestrial habitat?
A terrestrial habitat should be set up exactly the same way as the land part of a semi-aquatic habitat. To create the high humidity that terrestrial caudates need, provide a shallow water bowl as well as lots of plants and moss.
-What kind of water should I use?
The water that you use must be free of chlorine and chloramine. If you are using tap water, you must treat it with a water conditioner or let it sit out for at least 24 hours to allow time for the dissolved gasses to dissipate. You can also use bottled spring water if you are concerned about the quality of your tap water.
-How do I maintain water quality?
Maintaining water quality is very important for the health of your salamander or newt. We recommend testing regularly for ammonia and nitrate and using a quality filter to keep the water clean. The size of the filter will depend on how big the habitat is and what volume of water it holds. Avoid using power filters, as these leave gaps in the lid where your salamander or newt could escape. Do partial water changes regularly - 10% every week or 20% every two weeks. Never change all the water unless you absolutely must because of health issues or serious water problems.
-What temperature is best for salamanders and newts?
The preferred optimum temperature range (POTR) will vary by species, but generally salamanders and newts should be kept at temperatures below 72°F. There are exceptions to this, but in most cases, you will not need to use any sort of heating products to maintain the proper temperatures. For example, Paddletail Newts require a water temperature that falls between 50° and 65°F, and Chinese Fire-belly Newts need a temperature of 60° to 70°F.
-Do salamanders and newts require special heating?
Never use hot or heat rocks, as these can seriously burn your caudate. Generally only tropical or semi-tropical species will require heating products, and you can use submersible aquarium heaters, incandescent lighting (daytime), nocturnal heat bulbs,under tank heaters and heat mats, and ceramic heat emitters. Whatever products you use should create a temperature gradient within the habitat. One side of the cage needs to be significantly cooler than the other to allow for thermoregulation.
-Do salamanders and newts need special lighting?
n most cases, no special lighting is required. However, amphibians do benefit from some exposure to UV light, as it will more accurately simulate their natural environment. We recommend the use of a UV bulb with a low output of UVB light for 12 hours each day. Use a timer to maintain proper photoperiods. Newts and salamanders are usually nocturnal, so you must turn off any visible light fixtures at night so as not to interrupt their natural nighttime behaviors. If you want to view them at night, you will have to use a nocturnal bulb.
-Does a screen mesh lid provide enough ventilation?
In most cases, a screen mesh lid will not be sufficient, and you will have to provide ventilation in other ways, such as drilling 1/4" holes near the top of acrylic or Plexiglas tanks or using an aerator system made from an aquarium pump, airline tubing, and an airstone or bubbler. Properly ventilating the habitat will prevent noxious odors from building up inside the enclosure and reduce the number of organisms growing in the soil, so it will keep your caudate's environment more sanitary.
-Do salamanders and newts hibernate?
Those that are native to climates with cold winters will need to hibernate during colder months, so you will need to adjust the temperatures within their habitat to enable this behavior. Speak to your veterinarian about proper care and housing before and during hibernation.
-Can I house different species of salamanders and newts together?
We do not recommend that you do this. Some species are toxic to other species or may attempt to eat them. Only similarly sized members of the same species should be housed together.
Newts as Pets – an Introduction to their Care and Feeding:
Although my interests are wide, newts and salamanders have always held a special fascination for me. Beginning in childhood, I sought to keep and breed as many species as possible, and I focused on their husbandry and conservation when I entered the zoo field. In time, I wrote a book summarizing my experiences (please see below). The passage of so many years has not dulled my enthusiasm for these fascinating amphibians, and I can highly recommend them to both beginning and advanced herp keepers.
The following information may be applied to the care of Japanese Fire-Bellied, Eastern, California, Ribbed and Paddle-Tailed Newts, as well as most others that appear in the pet trade. Please write in for detailed information on individual species.
Newts as Pets :
An ability to thrive on commercial pellets distinguishes newts from other amphibians, and endears them to folks who prefer not to handle live insects. All are brilliantly-colored, active by day, and usually live well in groups at average room temperatures. Most become quite tame over time, and will even accept food from your hand. Several California Newts in my collection have lived to age 20, and others seem bent on exceeding that.
Natural History :
The term “newt” is usually applied to small, semi-aquatic salamanders in the family Salamandridae. This family contains 80+ species that range throughout North America, Asia and Europe. During the breeding season, males usually develop bright colors, and some, such as the Banded and Crested Newts, sprout fantastic skin crests. The Ribbed Newt may reach a foot in length, but others average 4-6 inches.
Newt larvae develop in water. Upon maturity, they pass through a land dwelling phase (see photo of Eastern Newt above) and then re-enter the water, where they remain for the balance of their lives. However, certain populations depart from the typical lifestyle; Eastern Newts on Long Island, NY, for example, skip the land stage.
Newts offered in the pet trade are usually in their adult, semi-aquatic stage.
Behavior:
Amphibians are not known for being especially active, but newts are always nosing about for food, exploring, and interacting with tank-mates. They see well and may swim to the aquarium’s side when you enter the room, in anticipation of a meal.
Handle newts only when necessary, and with wet hands so that the skin’s protective mucus covering is not removed.
Housing:
Setting up the Habitat:
Newts are well-adapted to life in the water, but do need a place to haul out and rest. The water in their aquarium can be deep, provided that egress is simple…cork bark, turtle platforms, and floating live orplastic plants all serve well as resting spots.
Newts are perfectly suited to aquariums stocked with live plants, and spectacular displays can be easily arranged (please see video below). Plants help maintain water quality, and the complex environments they create make life more interesting for both newt and newt-owner.
As newts readily climb glass, a secure screen cover is a must.
Substrate:
Smooth, rounded gravel of a size that cannot be swallowed is ideal; rough stones will injure the delicate skin. Bare-bottomed tanks are easily kept clean.
Water Quality:
Newts have porous skins that allow for the absorption of harmful chemicals. Careful attention to water quality is essential.
An aquarium pH test kit should always be on hand. Most newts fare well at a pH of 6.5 to 7.5, with 7.0 being ideal.
Ammonia, excreted as a waste product and produced via organic decomposition, is colorless, odorless andextremely lethal to newts; a test kit should be used to monitor its levels.
Chlorine and chloramine must be removed from water used for any amphibian. Liquid preparations are available at pet stores.
Copper may be leached by old water pipes; a test kit should be used if you suspect its presence.
Filtration:
Undergravel, sponge, corner, hanging and submersible filters can all be used in newt aquariums. Even with filtration, regular partial water changes are essential in keeping ammonia levels in check.
As newts are not strong swimmers, water outflow from the filter should be mild; plants, rocks and movable outflow attachments can be used to reduce current strength.
Light and Heat:
Newts seem not to require UVB light. UVA light is not essential, but may encourage natural behaviors.
Most newts thrive at normal household temperatures, but fare best when kept cool (60-68 F). Temperatures above 75 F may weaken the immune systems of some. Please write in for information on individual species. A winter cooling period of 40-50 F encourages reproduction.
Companions :
Although often sold as “additions” to tropical fish aquariums, newts do poorly in warm water and feed too slowly to compete with most fishes. Guppies adjust well to cool water, and their fry will be eagerly consumed by newts; limit the number of adults so as to avoid competition for food. Weather Loaches andCorydoras Catfishes will co-exist, and usually do not interfere with feeding.
Feeding:
I rely upon Reptomin Food Sticks as a mainstay for the newts in my collection, and for those under my care in zoos. Freeze-dried shrimp (included in Reptomin Select-a-Food) “gelled insects”, canned snails and frozen fish foods (i.e. mosquito larvae) should be offered regularly.
Live food, while not essential, is relished and will help ensure a balanced diet. Blackworms, bloodworms, earthworms, guppies, and small crickets will be eagerly accepted. Stocking the aquarium with live blackworms will keep your pets active and occupied.
Newt larvae and terrestrial sub-adults will usually accept only live food. Please write in for further information.
Health Considerations :
Newt skin glands produce toxins such as Tarichatoxin, which can be fatal if ingested (so don’t eat your pet!). Do not handle newts when you have an open cut, and always wash well afterwards. Toxins transferred to the eyes via fingers have caused temporary blindness.
1- Axolotl :
Ambystoma mexicanum
From Wikipedia, the free encyclopedia
The axolotl (/ˈæksəlɒtəl/; etymol. Nāhuatl āxōlōtl [aːˈʃoːloːt͡ɬ] (singular) or āxōlōmeh [aːˈʃoːloːmeʔ] (plural) "water monster"),[2] also known as a Mexican salamander (Ambystoma mexicanum) or a Mexican walking fish, is a neotenic salamander, closely related to the tiger salamander.[3][4] Although the axolotl is colloquially known as a "walking fish", it is not a fish, but an amphibian. The species originates from numerous lakes, such as Lake Xochimilco underlying Mexico City.[5] Axolotls are unusual among amphibians in that they reach adulthood without undergoing metamorphosis. Instead of developing lungs and taking to land, the adults remain aquatic and gilled.
Axolotls should not be confused with waterdogs, the larval stage of the closely related tiger salamanders (A. tigrinum and A. mavortium), which are widespread in much of North America and occasionally become neotenic. Neither should they be confused with mudpuppies (Necturus spp.), fully aquatic salamanders which are not closely related to the axolotl but bear a superficial resemblance.
As of 2010, wild axolotls were near extinction[6] due to urbanization in Mexico City and consequent water pollution. They are currently listed by CITES as an endangered species and by IUCN as critically endangered in the wild, with a decreasing population. Axolotls are used extensively in scientific research due to their ability to regenerate limbs.[7] Axolotls were also sold as food in Mexican markets and were a staple in the Aztec diet.
A four-month-long search in 2013 turned up no surviving individuals in the wild. Previous surveys in 1998, 2003 and 2008 had found 6000, 1000 and 100 axolotls per square kilometer in its Lake Xochimilco habitat, respectively.
Description :
A sexually mature adult axolotl, at age 18–24 months, ranges in length from 15–45 cm (6–18 in), although a size close to 23 cm (9 in) is most common and greater than 30 cm (12 in) is rare. Axolotls possess features typical of salamander larvae, including external gills and a caudal fin extending from behind the head to the vent.
Their heads are wide, and their eyes are lidless. Their limbs are underdeveloped and possess long, thin digits. Males are identified by their swollen cloacae lined with papillae, while females are noticeable for their wider bodies full of eggs. Three pairs of external gill stalks (rami) originate behind their heads and are used to move oxygenated water. The external gill rami are lined with filaments (fimbriae) to increase surface area for gas exchange.
Four gill slits lined with gill rakers are hidden underneath the external gills.
Axolotls have barely visible vestigial teeth, which would have developed during metamorphosis. The primary method of feeding is by suction, during which their rakers interlock to close the gill slits. External gills are used for respiration, although buccal pumping (gulping air from the surface) may also be used to provide oxygen to their lungs. Axolotls have four pigmentation genes which when mutated create different colour variants. The normal wild type animal is brown/tan with gold speckles and an olive undertone. The four mutant colors are leucistic (pale pink with black eyes), albino (golden with gold eyes), axanthic (grey with black eyes) and melanoid (all black with no gold speckling or olive tone). In addition there is wide individual variability in the size, frequency, and intensity of the gold speckling and at least one variant that develops a black and white piebald appearance on reaching maturity. Because pet breeders frequently cross the variant colours, animals that are double recessive mutants are common in the pet trade, especially white/pink animals with pink eyes that are double homozygous mutants for both the albino and leucistic trait. Axolotls also have some limited ability to alter their colour to provide better camouflage by changing the relative size and thickness of their melanophores.
Habitat and ecology:
The axolotl is only native to Lake Xochimilco and Lake Chalco in central Mexico. Unfortunately for the axolotl, Lake Chalco no longer exists, as it was artificially drained to avoid periodic flooding, and Lake Xochimilco remains a remnant of its former self, existing mainly as canals. The water temperature in Xochimilco rarely rises above 20 °C (68 °F), though it may fall to 6 to 7 °C in the winter, and perhaps lower.
The wild population has been put under heavy pressure by the growth of Mexico City. The axolotl is currently on the International Union for Conservation of Nature's annual Red List of threatened species. Non-native fish, such as African tilapia and Asian carp, have also recently been introduced to the waters. These new fish have been eating the axolotls' young, as well as its primary source of food.
Axolotls are members of the Ambystoma tigrinum (Tiger salamander) complex, along with all other Mexican species of Ambystoma. Their habitat is like that of most neotenic species—a high altitude body
of water surrounded by a risky terrestrial environment. These conditions are thought to favor neoteny. However, a terrestrial population of Mexican Tiger Salamanders occupies and breeds in the axolotl's habitat.
The axolotl is carnivorous, consuming small prey such as worms, insects, and small fish in the wild. Axolotls locate food by smell, and will "snap" at any potential meal, sucking the food into their stomachs with vacuum force.
Three Colors of Axolotl
Neoteny :
Axolotls exhibit neoteny, meaning they reach sexual maturity without undergoing metamorphosis. Many species within the axolotl's genus are either entirely neotenic or have neotenic populations. In the axolotl, metamorphic failure is caused by a lack of thyroid stimulating hormone, which is used to induce the thyroid to produce thyroxine in transforming salamanders. The genes responsible for neoteny in laboratory animals may have been identified; however, they are not linked in wild populations, suggesting artificial selection is the cause of complete neoteny in laboratory and pet axolotls.
Neoteny has been observed in all salamander families in which it seems to be a survival mechanism, in aquatic environments only of mountain and hill, with little food and, in particular, with little iodine. In this way, salamanders can reproduce and survive in the form of a smaller larval stage, which is aquatic and requires a lower quality and quantity of food compared to the big adult, which is terrestrial. If the salamander larvae ingest a sufficient amount of iodine, directly or indirectly through cannibalism, they quickly begin metamorphosis and transform into bigger terrestrial adults, with higher dietary requirements. In fact, in some high mountain lakes also live dwarf forms of salmonids, caused by deficiency of food and of iodine, in particular, which causes cretinism and dwarfism due to hypothyroidism, as it does in humans.
Unlike some other neotenic salamanders (sirens and Necturus), axolotls can be induced to metamorphose by an injection of iodine (used in the production of thyroid hormones) or by shots of thyroxine hormone. The adult form resembles a terrestrial plateau tiger salamander, but has several differences, such as longer toes, which support its status as a separate species.
Axolotl in captivity
Use as a model organism:
Six adult axolotls (including a leucistic specimen) were shipped from Mexico City to the Jardin des Plantes in Paris in 1863. Unaware of their neoteny, Auguste Duméril was surprised when, instead of the axolotl, he found in the vivarium a new species, similar to the salamander. This discovery was the starting point of research about neoteny. It is not certain that Ambystoma velasci specimens were not included in the original shipment.
Vilem Laufberger of Germany used thyroid hormone injections to induce an axolotl to grow into a terrestrial adult salamander. The experiment was repeated by Englishman Julian Huxley, who was unaware the experiment had already been done, using ground thyroids. Since then, experiments have been done often with injections of iodine or various thyroid hormones used to induce metamorphosis.
Today, the axolotl is still used in research as a model organism, and large numbers are bred in captivity. They are especially easy to breed compared to other salamanders in their family, which are almost never captive-bred due to the demands of terrestrial life. One attractive feature for research is the large and easily manipulated embryo, which allows viewing of the full development of a vertebrate. Axolotls are used in heart defect studies due to the presence of a mutant gene that causes heart failure in embryos. Since the embryos survive almost to hatching with no heart function, the defect is very observable. The axolotl is also considered an ideal animal model for the study of neural tube closure due to the similarities between human and axoltol neural plate and tube formation, which unlike the frog, is not hidden under a layer of superficial epithelium. There are also mutations affecting other organ systems some of which are not well characterized and others that are. The genetics of the colour variants of the axolotl have also been widely studied.
The feature of the salamander that attracts most attention is its healing ability: the axolotl does not heal by scarring and is capable of theregeneration of entire lost appendages in a period of months, and, in certain cases, more vital structures. Some have indeed been found restoring the less vital parts of their brains. They can also readily accept transplants from other individuals, including eyes and parts of the brain—restoring these alien organs to full functionality. In some cases, axolotls have been known to repair a damaged limb, as well as regenerating an additional one, ending up with an extra appendage that makes them attractive to pet owners as a novelty. In metamorphosed individuals, however, the ability to regenerate is greatly diminished. The axolotl is therefore used as a model for the development of limbs in vertebrates.
Captive care:
It is a popular exotic pet like its relative, the tiger salamander (Ambystoma tigerinum). Axolotls live at temperatures of 12 to 20 °C (54 to 68 °F), preferably 17 to 18 °C (63 to 64 °F). As for all poikilothermicorganisms, lower temperatures result in slower metabolism; higher temperatures can lead to stress and increased appetite. Chlorine, commonly added to tapwater, is harmful to axolotls. A single typical axolotl typically requires a 40-litre (11-US-gallon) tank with a water depth of at least 15 cm (6 in). Axolotls spend a majority of the time at the bottom of the tank.
Salts, such as Holtfreter's solution, are usually added to the water to prevent infection
In captivity, axolotls eat a variety of readily available foods, including trout and salmon pellets, frozen or live bloodworms, earthworms, and waxworms. Axolotls can also eat feeder fish, but care should be taken as fish may contain parasites
There are persistent statements in pet care literature that axolotls cannot be kept on gravel because gravel causes fatal digestive impaction. There is no evidence to support this myth and counter evidence that normal healthy axolotls regularly ingest gravel and pass it without any negative consequences. The axolotl, like many amphibians, may be deliberately ingesting gravel to act as a gastrolith providing buoyancy control and aiding digestion, preventing impaction, rather than causing it. Axolotls deprived of appropriately sized gravel will ingest anything else they can find while attempting to satisfy their instinctive need for gastroliths and this behaviour, combined with lack of appropriate gastroliths, may be a cause, among others, of fatal impaction
These axolotls at Vancouver Aquarium are leucistic, with less pigmentation than normal.
How to Successfully Keep Your New Axolotl :
Courtesy to : www. aqualandpetsplus . com
Axolotl Factoids:
Origin : Mexico City
Albino Origin : Reared in captivity
Sexing : Males “lumpy” at back legs.
Temperature : Keep in unheated aquaria
Attitude : Frequent biter of tank mates
Substrate : Likely to eat gravel
Security : None needed. Mean.
Foods : Crickets, fish, worms
Supplements : None needed
Housing : At least a gallon of water per
axolotl
Water : Clean water – preferably hard
Breeding Age : One year
Incubation : About 3 weeks
Brood Size : 200 to 600 eggs
Axolotl threat : Dedicated cannibals
Comment : Separate adults after breeding
Axolotls vs. Waterdogs.
Axolotls look like water dogs with a different number of back toes. As a result, we usually order only the albino form because we can’t tell them apart. Both are “nippers” to the max. They bite off each others’ gills and feet. Happily, axolotls and water dogs grow back these lost parts if you separate them.
Above is Axolotl and below is Water Dog ..
Recommended Foods. In the wild, these guys eat bugs, worms (one of their favorites), fish, tadpoles, and parts of slower axolotls. In captivity, axolotls eagerly eat commercial turtle sticks and/or pellets. They also love most frozen fish foods -- and live worms. Feed larger worms as they grow. This makes them easy to keep. Just make sure that you remove any uneaten food. Bad water kills axolotls. You need to feed the adults only three or four times per week.
Un-recommended Foods. Axolotls will eat pieces of meat. Since they rarely eat cows or pigs in the wild, you’d do best to avoid meat in their diet -- they cannot digest the fat.
Food II. Several reports say Mexicans eat axolotls. We don’t know whether to believe these reports or not. Axolotls are an endangered species where they come from. That makes them expensive besides not being at all tasty looking.
To the right is the axolotl and to the left is a water dog ..
Eating Comments. :
Axolotls suddenly Hoover their food. They open their mouth in such a way that whatever’s near gets sucked in. Very much like an oscar’s enthusiastic gulp -- without the audible pop. Unfortunately, this often includes gravel since they eat food “off the floor.” Axolotls can probably process small gravel. Larger gravel often presents a real problem. In addition to anchoring them to the bottom like a load of ballast, gravel can plug up their digestive system. Luckily, they usually spit it out -- but not always.
Not the best substrate. Feeding axolotls can ingest gravel.
Axolotls tend to snap at whatever's close.
Axolotls will gorge themselves on small goldfish. Same guy as in middle of pic above.
You needn't feed your axolotl every day.
Appeal. :
If you like bitey little predators, you’ll like these guys. Axolotls bite anything that goes past their mouths. Their eyesight is not the greatest. They locate their food by smell or by feeling it moving through the water. But most people keep them because they look intriguing. Their albino bodies, pink eyes, dainty toes, and decorative fringed gills all catch your eye.
Not Good Mixers. :
Axolotls bite their tank mates every chance they get. They will always eat smaller tank mates and chew on the equal-sized ones. The laboratories that raise them house each in a separate container about the size of a half-gallon ice cream carton.
Xolotl: In Mexican mythology Xolotl is the god of games. He is the twin brother of the better known Quetzecoatl. Axolotls originally came from the lakes below today’s Mexico City. Some people translate axolotl as water beast or water dog or water doll or water whatever.
Not many critters will eat tadpoles. Axolotls (probably a female here) will.
When you see those white spots appear, you should have changed their water yesterday.
Water. Axolotls thrive in hard, alkaline water (like comes out of our Des Moines faucets). Age it, of course. Add NovAqua to remove the chlorine and any heavy metals. Then add one teaspoon of salt per gallon to make primo water. Making perfect water decreases your chances of disease. Most axolotl problems stem from dirty water. Also, careful with those power filters. Too much current stresses them.
Obviously, this axolotl would rather you leave her alone.
To the right is the axolotl and to the left is a water dog ..
If you insist on handling axolotls, slowly come up from underneath.
This little guy kept biting at me till I turned him loose. (It did not hurt.)
Can You Handle Them? You can try. Axolotls dislike being grabbed. We do not recommend handling axolotls (or other amphibians) any more than necessary. Scraping their skin can cause bacterial and fungal infections. And keep all raw amphibians out of your mouth.
Breeding Axolotls. Separate the sexes for a period of time. Then put your pair in a shallow container with gravel on the bottom. (He attaches his spermatophores to the gravel. The female picks them up.) He’ll “court” her by nuzzling her a bit. She’ll usually lay eggs within 24 hours after picking up the male’s spermatophores. She prefers to lay her eggs on floating plants. Remove her before they hatch or she will probably eat the larvae.
Larvae Care. After the larvae start swimming, feed them infusoria and newly hatched brine shrimp (or microworms). Keep them well fed and change their water often. Wait three months between spawnings to allow her to recoup her resources. Axolotls spawn better when the days are longer.
Axolotl mouths aren't really big enough to bite you, however, bigger ones will try.
Do They Bite? Of course. Tank mates beware. However, they will not likely bite you. If you feed them small worms from your fingers, your chances of getting bitten go way up. Axolotls (and water dogs) pretty much just bounce off your fingernails.
Salamanders lose these external gills. Axolotls keep their gills forever.
Axolotls come in several colors.
Another color
Vocabulary Lesson. Axolotls never (well, hardly ever) turn into salamanders like their cousins the waterdogs. However, even though they keep their fringed gills, the adults also develop lungs. They keep their external juvenile form (the fringed gills) even when they mature. This trait is known as neotony.
Unrelated Extra Info. We put this guy in a fallow tank that previously housed Yucatan crayfish. The next morning he was covered with these baby leeches. The little blood suckers really nailed this guy.
He's in a two-inch bowl here. Lotsa leeches too tiny to pick off.
We added one teaspoon of salt and the leeches started dropping off.
More than we cared to count -- not counting the ones on the hand shown above.
Leech Info. Evidently leeches can lie in wait without food for extended periods of time. We dosed that fallow tank with salt and zapped many more baby leeches. But they still lived. So we gave them a couple cups of salt and the tank still lies fallow.
Breeding Axolotls :
Courtesy to : www.axolotl.org
Axolotls can reach sexual maturity anywhere between 5 months and several years, depending on frequency and quality of food, and the water temperature and conditions in which the animals are kept. My personal record for a fully mature male is just under 6 months (at 25 cm or 10 inches).
Axolotls generally begin to mature once they have reached about 18 cm (7 inches) in total length. Females tend to take a little longer to mature than males (usually a difference of a month or two).
It is advisable that you don't attemt to breed axolotls until they reach at least 18 months of age. This gives them time to reach their full size (greater than 30 cm or 12 inches in many cases) and condition (a female ready to breed will be very round towards the end of the body when viewed from above). In my opinion it is safe to breed males at an earlier stage than females, because they have much less physical output during the mating process than females, and therefore there is less strain on their bodies. However, females should be prevented from breeding until they reach their full size.
There is a very good reason for not breeding your female axolotl(s) too early. A female axolotl can lay in excess of 1000 eggs. Producing so many eggs is a strain on the animal's metabolism, and the body prioritises production of eggs over body growth while the animal is in conditions suitable for breeding. Since females may breed several times each year, as soon as the first batch of eggs are laid, the body attempts to produce new eggs to replace those that have been laid. Female axolotls may fall ill at this point unless due care is taken, and for a female that is still growing in length, the strain is increased. For the same reason, females that have recently bred should be kept away from males for at least a month, preferably two or three, in order for them to recover. From personal experience, I know that just because an axolotl breeds, it doesn't mean it is in good overall health.
Axolotl sexing :
The first photo below is of the cloacal region of a mature male and the second is of a mature female's cloacal region. The male is a golden albino, while the female is a melanoid albino. Their cloacas are circled in blue.
Axolotl eggs
Male Golden Albino
Female melanoid albino
Breeding methods :
Most sources state that the breeding season for axolotls is from December to June. However, they can be bred at any time of the year, although most success is reported in the early part of the year. The former Indiana University Axolotl Colony used changes in the length of light period to trigger spawning. Males and females are subjected to a decreasing "daylight" period over a few weeks, and then the duration of lighting is steadily increased. They then put a male and a female together and courtship behaviour usually follows.
An alternate school (Peter W. Scott and some others) instead recommends a sudden change in temperature to trigger courtship behaviour. Keeping the pair separately for a few weeks at 20-22 °C (68-71 °F) and then transferring them both into a tank with a water temperature at least 5 °C lower frequently triggers courtship behaviour. In fact, Scott recommends 12-14 °C (54-57 °F). My own experience, and that of some others, is that this thermal shock method usually just stimulates the male. In order for this procedure to be successful, the female most be receptive and ready to breed.
In my experience, by keeping axolotls in a room that receives at least partial seasonal change in temperature and light period (if there is a window in the room), breeding will occur naturally, usually at least once before the peak of winter and once in the spring, if the animals are adequately fed.
As mentioned briefly above, exposure to natural day length throughout the year by having the tank in a room that receives natural light is a good idea because light seems to have at least as an important role as temperature in simulating the seasons.
A pair of axolotls kept in good conditions should breed at least once a year, albeit unpredictably. Axolotls may spawn for no obvious reason, at "odd" times of the year, as mine have done in the past. Axolotls may surprise you.
My Breeding Setup:
The breeding setup that I use routinely is furnished with many plants (plastic plants are good because they don't rot, but I also use clumps of live Java Moss, Vesicularia dubyana). The plants are for the female axolotl to affix her eggs (pictured on the right is a female melanoid albino in the process of laying its eggs on plastic plant leaves). Slates or flat, rough pieces of stone should be placed on the bottom of the tank for the male to deposit its spermatophores. Spermatophores are packets of sperm - you can read more on these in the courtship and spawning section. Spermatophores will not readily stick to bare glass or plastic, so in order for mating to be successful the spermatophore must be stationary during courtship. It is usually a good idea to put the tank in a room where it will be left alone, so as not to disturb the pair.
Courtship and Spawning:
Spawning is initiated by the male, who swims around, raising its tail and making vigorous writhing motions. The male nudges the female's vent occasionally and then leads her around the tank. The spermatophore is a common "device" in the salamander and newt world (an old one, about 12 hours old, is pictured beside this paragraph). It is a packet of sperm attached to the top of a cone of jelly. The male deposits between 5 and 25 of these around the tank and attempts to lead the female over them. She picks up the sperm cap (from one or more spermatophores) in her cloaca - fertilisation takes place internally. She may also nudge the male's vent, and this can lead to a prolonged "dance" around the tank.
Between a few hours and two days later, she commences spawning, laying each egg individually. She will lay them on the leaves of plants, if available, but if not, she will place them about the tank, attaching them to rocks, pipes and any other object available. There may be between 100 and over a thousand eggs laid in one spawning, depending on the size of the female and if she is in optimal condition at spawning. After the female has finished laying, it's best to remove her and the male.
Hatching Eggs :
Pictured to the right are four 12-hour old eggs. Note the lack of pigment - this indicates that the mother was albino. Normal eggs are dark brown (there is a picture of two at the top of this page). An albino mother will lay white, pigmentless eggs. If the offspring are not albino, pigment will appear during embryo development. The eggs take about 2 to 3 weeks to hatch. Development seems to be optimal when the eggs are attached to plants. This is due to the circulation of water around the egg, aiding gaseous exchange.
Assuming the eggs are fertile, the majority of the eggs should hatch if kept in well-aerated water. An air pump and air stone at one end of the tank will be helpful, just be sure it doesn't cause vigorous water flow. At 20 °C (68 °F) the eggs should hatch after about 17 days. Have a look at the Embryo Series Photo Log for a daily photographic account of the development of some white eggs.
Rearing Axolotls:
I first bred axolotls successfully in the late 1990s. Thankfully I was very successful. By following the advice and directions on this page, you should be too. Axolotl larvae are surprisingly tough, as far as newt and salamander larvae go. By the way, "larvae" is the plural of larva, the term used to describe axolotls (and other newts and salamanders) that have yet to develop all four legs. Due to their toughness, if we follow the guidelines on this page we shouldn't have any major problems rearing the larvae.
We should bear in mind that there will always be a few casualities when rearing large numbers of larvae. Some larvae will have "unseen" genetic problems, some will succumb to stress that others will survive, and some will just be plain unlucky. For the beginner, it is most advisable to attempt to rear only a few larvae at a time. It's better to give away or, though it may seem unpleasant, cull most of the eggs, giving the remainder all of your attention and resources, than to try to rear many hundreds of larvae for the first time and see them all die due to stretched resources, bad water conditions, or other problems frequently encountered by beginners. If you have too many eggs, you will find plenty of people willing to accept them from you on the Caudata.org Forum. Likewise, if you are looking for axolotl eggs or young axolotls, you will find them there too. Unusual colours, like the melanoid axolotl larva we can see at the top of this page developing in its egg
Female axolotl laying eggs..
Initial care of eggs :
Finding axolotl eggs, or seeing a female spawning, often occurs when we least expect it, or at least not quite on the day we expect. It's always a good idea to keep an eye out for old spermatophores in the parents' tank so that we have some warning that there may soon be many new mouths to feed.
On finding eggs, we must decide if they are to be removed, or the parents are to be removed and the eggs left behind. Many first time breeders opt for the latter choice, but axolotl eggs are quite tough, so the eggs can usually be removed from a tank and moved to another without issue. They can even be removed from rocks if you're careful: there is generally a point of attachment to the egg's outermost jelly layer, which can be sliced with a finger nail, thus freeing the egg. Each egg is surrounded by several layers of jelly, so don't be too afraid. Eggs attached to plants are great, because they will stick to the plants. The plants can be moved carefully to the new tank, thus avoiding all hand contact with the eggs themselves.
A Female with eggs
Once you have made your choice (to move or not to move the eggs), it's time to make sure we have correct conditions for the eggs to hatch. Pictured to the left is a small aquarium (45x20x25 cm, 18x8x10 inch) solely for hatching eggs (I opted to hatch just 100 in this case). Remember to use dechlorinated water. Water shouldn't be soft: do you get limescale in your water pipes or kettle? If you get limescale, your water isn't soft. If you're not sure, you should read theRequirements Page for more information about dissolved salts and their importance.
Our next concern is water temperature. Keeping the eggs at a warm temperature (to an absolute maximum of 25 °C /77 °F) will cause the eggs to hatch sooner (generally in less than 14 days), whilst a lower temperature (such as 18 °C / 64 °F) will result in them taking perhaps more than 20 days. Being able to manipulate the time taken to hatch can be very useful if you need a while to secure a food source for the newly hatched axolotls. By lowering the temperature you can give yourself an extra week or two in order to acquire some brineshrimp eggs, culture your Daphnia, or order some microworms from a dealer.
Food :
Speaking of food for little mouths, it's time we considered our options. If you bred your axolotls deliberately, the chances are you are already setup as far as providing tiny live food items is concerned. More often than not though, we need to acquire these food items in a hurry. Newly hatched axolotl larvae can vary in size from 10-13 mm (roughly 0.5 inch). On hatching, they will still possess some egg yolk in their stomachs (the white substance that should be quite visible to the naked eye). Until this is used up they will be motionless and won't require food.
Within 24-72 hours after hatching, they will require food. From this point until they reach approximately 20 mm in length (a little under an inch), their diet must consist solely of livefood items of a very small size. They will ignore dead food until they have grown significantly. This is because, instinctively, young larvae respond to prey movement alone. It is not until later that smell will play an important role in feeding. If you cannot meet this demand for tiny live food, your larvae will starve to death, unless they eat each other (very hard to do for newly hatched larvae). For newly hatched larvae, the live food choices are: newly hatched brineshrimp (Artemia), smallDaphnia (see the photo on the right) or Moina, and microworms (microworms are not ideal and won't be well received until the axolotl larvae develop their front legs). There is an excellent article about tiny live foods at the Caudata Culture web site, and I recommend you read that before proceeding.
There is a good article about foods for newly hatched salamanders over at Caudata Culture. Here's a link to that article.
My preference is to feed young Daphnia, with some microworms as back up. I culture both, myself. I wouldn't recommend feeding wild-caught Daphnia or Daphnia obtained from an unknown source when feeding axolotls, or even fish. They have been known to carry diseases if taken from nature or sources containing other animals. Culturing your own, however, removes most of this danger, and although not as small or quite as nutritious as newly-hatched brineshrimp (young Daphnia are approximately two and a half times the size of newly hatched brineshrimp), youngDaphnia are a good first food for axolotl larvae, and they can be free! I feed mine on crushed trout pellets (the same ones I feed the axolotls). The Daphnia don't actually eat the pellets but rather the bacteria that grow as a result of the leeching of nutrients from the pellets into the water.
Microworms aren't the most nutritious food - axolotls fed solely on these will grow very slowly, and won't be received well by larvae that have yet to develop their front legs. They are a good food when you are in need though.
After Hatching :
On hatching, most axolotl larvae are about 11 mm (less than half an inch) in length. Just before hatching I normally lower the water level to about three or four centimetres (an inch and a half) so that any daphnia in the tank are concentrated near the larvae for easy access. Once most of the larvae have hatched, it is a good idea to tear the jelly coat of those eggs that haven't hatched yet in order to free the larva inside. This can be done with a sharp forceps or narrow scissors that is inserted into the egg and then the prongs/blades are pushed apart.
As explained earlier, at this stage the larvae usually won't eat because they're still absorbing the yolk from their eggs. You should be ready with your chosen first food. I normally have some Daphnia in the tank a few days before hatching in order to have lots of little tiny young Daphnia present when needed. The larvae can get air bubbles in their stomachs if not fed early enough, but these will be expelled once they start to feed.
Very young larvae can be kept together without much risk of cannibalism since this really only begins once the front legs develop. When very young they should be fed frequently (once or twice daily). If kept at about 20 °C (68 °F) they should reach about 1.5 cm in length within a week. The larva pictured below is four days old and 14 mm in length. It is D/D M/m a/a (see the Genetics Page for more information about colour). If feeding brineshrimp, at least some of the water should be replaced each day because newly hatched brineshrimp die quickly in fresh water and can foul the water in a matter of hours. As mentioned above, Daphnia will live in the tank with the larvae until eaten, so occasional water changes are fine (partial water changes a few times a week).
four days old and 14 mm in length larva
Larvae never grow at the same rate, so it is advisable to divide them up according to size once they begin to reach about 2 cm in length. At this size the larvae become more cannibalistic, since they snap at anything that moves and at that size can damage their siblings (missing limbs and gills are an obvious sign). The larva -left is a D/D m/m a/a sibling of the larva above at 7 days old. It is 19 mm in length.
Cannibalism is a natural tendency, and studies have been carried out on the cannibalistic variants of salamander larvae. If left to cannibalise their siblings, they actually develop different morphology (shape and appearance). This is most noticeable in the shape of the head and the teeth. James Petranka's Book, "Salamanders of the United States and Canada" discusses cannibalism in detail, especially in the case of the Tiger Salamander, with some excellent photography, and William Duellman and Linda Trueb's book, "Biology of Amphibians", contains some excellent diagrams of the head morphology of the different morphs of the tiger salamander, a close relative of the Axolotl (see the Books and Links Page).
In young larvae, particularly melanoid albino larvae like that on the left, you can actually see the liver, heart, stomach and intestines right through the skin. To minimise cannibalism, Peter Scott recommends that the tank is heavily planted and that light levels are lowered. A more reliable method is to reduce the numbers as much as possible in each container, but appetite does seem to decrease in low light.
It's been my experience that front legs begin to develop once the larvae reach 20 mm (within about 9 days of hatching at about 22 °C) and the hind legs begin to develop at the end of the third week. This all depends on temperature and feeding. The lungs first develop around the time that the rear-legs develop (yes, axolotls do possess lungs as well as gills). As the larvae grow they need to be thinned out, and any deformed or markedly inferior larvae (such as those that don't re-grow limbs and gills easily) should be euthanised/culled. There has been a lot of inbreeding in axolotls over the many years they have been kept in captivity, and this means that the likelihood of defects and oddities developing is greatly increased in this species.
Using the conditions just described, at 7 days, I still feed young Daphnia to the larvae, and most of the larvae are about 18 mm in length. At 9 days, most larvae have very noticeable front limb buds and most are about 20 mm in length. This is a high growth rate and I attribute it to the daily feeding of young Daphnia and the temperature at which they are kept (22 °C).
The golden albino larva on the right is 10 days old and is 22 mm in length. The arrow is pointing at a limb bud. At this size they eat adult Daphnia (which are 2.5-3 mm in length). At 25 mm (1 inch) I try to maintain a maximum of 25 larvae per 45x20x25 cm aquarium. Remember, if you have too many larvae, either find new homes for them or cull them to prevent disasters. At 25 mm, hind leg buds should be quite apparent on most larvae and some should have well-developed front legs.
At this point it is possible to begin feeding the larvae with thawed frozen bloodworm (see the Feeding Page). These can replace partially, or fully, the small live foods you've been using up to this point. If you've been keeping up with the appetites of the larvae, you will probably be running low on live food any way.
The photo on the left shows a 32 mm melanoid albino larva (D/D a/a m/m). At this stage its front legs are almost fully grown and hind leg buds are quite visible from the side (not visible in this photo though). Note the lack of iridophores (shiny pigment) in this larva, due to it being homozygous for the melanoid gene m. Xanthophores are almost absent in this larva, another effect of the melanoid gene.
At 36 mm, the colour phenotype of each larva is generally very apparent - this means you can tell different colour types apart quite readily. The front legs are now fully grown and the hind legs are growing.
At 40 mm (1.5 inches), the hind legs are about half grown. At this size, cannibalism can be a noticeable problem, so do try to keep the numbers in each tank at a low number (in the tank mentioned above, try to keep less than tens 40 mm larvae together). Feet and gills will still regrow rapidly on larvae at this size, however the older they get, the slower regeneration occurs. Another fact to be aware of is that wild type larvae tend to be more aggressive than non-wild types. Wild types will also show a tendency to attack non-wild types rather than other wild types.
You can use biofoam filters to try to reduce the number of water changes. These aren't great filters for animals like axolotls, but for larvae they are quite safe (no risk of sucking up larvae). If you know what you're doing, you could use a canister/external filter on a large aquarium. You will need to make sure that the input is protected from sucking up larvae, and the output flow spread out so that it doesn't stress the larvae (excessive water flow is a common cause of stress in axolotls, leading to disease).
Juveniles :
The larvae in the photo to the right are about 50 mm (2 inches) in length. The hind legs are not fully grown at this point but are quite visible. At this size they are more than capable of taking the 3 mm axolotl pellets.
Once the hind legs are fully developed, the larvae are now miniature versions of the adults, so they should now be called juveniles, or sub-adults. Growth should be steady, and juveniles are quite capable of taking small pieces of earthworm (or whole earthworms that are small in size).
If you find frozen bloodworm expensive and messy, it's worth knowing that at about 2.5-4 cm (1-1.5 inches) most laboratories begin feeding with axolotl pellets. Be sure to gradually changes foods though, rather than doing so abruptly: it may take a few days before the animals begin to take the "new" food.
If you would like to know more about the stages of larval growth, look at the Biology Page. There is a nice diagram of the stages of axolotl growth, from egg to juvenile.
The photo below shows 15 cm (6 inches) juveniles of various colours
2- Amphiuma :
Courtesy to : www.caudata.org
- Amphiuma pholeter
One-toed Amphiuma
- Amphiuma means
Two-toed Amphiuma
- Amphiuma tridactylum
Three-toed Amphiuma
Synonyms : Congo Eel
Range : Southeastern USA
IUCN Red Book : Near threatened (pholeter)
Least concern (means)
Least concern (tridactylum)
CITES : No listing
First described : Neill, 1964 (pholeter)
Garden and Smith, 1821 (means)
Cuvier, 1827 (tridactylum)
-Amphiuma pholeter: the one-toed amphiuma, has limbs and a head that are proportionately shorter than A. means or A. tridactylum. In addition, A. pholeter has a single gill opening on each side of the head and very small eyes. The dorsal and ventral areas of the salamander are of almost the same shade and are usually a darkish gray or grayish-brown. Adults of this species reach a maximum of 33 cm (12.9 inches) in total length, making this the smallest of the three species. There are no recorded conspicuous external sexual characteristics.
The three species of the Amphiumidae appear very similar to each other, with the primary difference being in the number of digits on each limb. Amphiuma pholeter has one digit on each foot, Amphiuma meanshas two, and Amphiuma tridactylum has three. In other respects, the species are similar, although there is a significant size difference between A. pholeter and the other two species at maturity. Another difference between A. pholeter and the other two species is that A. pholeter lacks costal grooves, while A. means andA. tridactylum have 57-60 costal grooves. All three species have long bodies, flat pointed heads, and vestigial limbs.
There is a wide variety of colloquial names for these salamanders, including “congo eel”, “conger eel”, “ditch eel’, “lamp-eater”, and “congo snake”. However, the accepted common names are based on the number of toes on their feet: one-toed amphiuma, two-toed amphiuma, and three-toed amphiuma.
-Amphiuma means : the two-toed amphiuma, is the largest of the three species, reaching a maximum size of 116 cm (45.6 inches) in total length. The laterally compressed tail can compose up to 25% of the total body length. The ventral surface is lighter in color than the dorsal surface, but does not sharply contrast with the dorsal surface. The dorsal color of this salamander ranges from black to dark brown to gray, although there are records of the occasional albino. As with A. pholeter, the eyes are small, and there is a gill slit on each side of the head. There are no recorded conspicuous external sexual differences.
- Amphiuma tridactylum: the three-toed amphiuma, is the second largest of the three species reaching a maximum size of 106 cm (41.7 inches) in total length. The laterally compressed tail can compose up to 25% of the total body length. As with the other two species, the eyes are small, and there is a gill slit on each side of the head. This species has the most contrast between the dorsal and ventral coloration, resulting in a sharply bicolored salamander. The dorsal coloration consists of black, slate gray, or a brownish color, while the ventral surface is light gray with a dark patch on the throat. Occasional albinos have been recorded from Mississippi and Missouri. A. tridactylum is sexually dimorphic, with females having dark cloacal walls while the males have whitish cloacal walls with oval papillose patches located on the lateral walls. (The inner cloacal walls can be observed by gently spreading open the walls, or waiting for a time when the cloaca is flexed and the inner walls can be seen.) During the reproductive season, sexually mature males will also develop a swollen cloaca.
Natural Range and Habitat :
All three species are restricted in distribution to the southeastern United States. The one-toed amphiuma has the most restricted range, occurring only in the northwestern portion of the Florida panhandle and in the southeastern portion of the gulf coast of Alabama. The two-toed amphiuma occurs throughout mainland Florida, west to Louisiana, and eastward along the coastal states to as far north as Virginia. The three-toed amphiuma occurs in the gulf-coast states from western Alabama, westward through Mississippi and Louisiana to eastern Texas, and north (following the Mississippi River) through much of Missouri and into eastern Arkansas, western Tennessee, and extreme western Kentucky.
Amphiuma species are aquatic, although they periodically can be found on land at night during rainstorms or when the females are brooding eggs. The normal habitat for all three species is either permanent or semi-permanent bodies of water such as canals, ponds, ditches, sloughs, rivers, or streams. All three species live in burrows in the mud at the bottom of the waterway, such as those made by crayfish In addition, all three species are able to make their own burrows. If the body of water in which the amphiumas reside dries up, they will burrow into the mud where, depending on the species and size, they can usually survive until the next rain.
Housing :
A. pholeter, the smallest of the three species, can be maintained in small groups of up to five individuals in a 76-liter (20-gallon long) aquarium. This species mainly dwells where soft mud gives way to firmer substrate at the bottom of the body of the water. This can be simulated by adding several inches of organic topsoil (make sure it does not contain manure or other soil amendments) and several handfuls of dried leaves to the aquarium when it is filled with water. This will provide the amphiumas with a habitat similar to that found in the wild. The only difficulty with this set up is that this prevents use of any power filter, as the filter will stir the up the mud and become clogged. The addition of floating plants such as duckweed, bladderwort, or water sprite will also help to mimic the natural habitat of this species. The major drawback to this sort of enclosure is that the animals will rarely if ever be visible. If viewing the salamander is important, then the soil can be omitted, but the addition of several handfuls of leaves to provide shelter on the bottom and a thick layer of floating plants should be provided. The best sort of filter for this sort of enclosure is a sponge filter, and weekly water changes of 10-15% should also occur.
The housing requirements for A. tridactylum and A. means are the same and consequently will be covered together. Cage size requirements are not as large as one might expect for a salamander of this size if housing the animal singly. For a strictly temporary set-up, they can be kept in buckets filled about ¼ of the way with water, with a secure lid over the top. Plastic storage bins can be used for long or short-term maintenance, as long as the bin is sized appropriately to the size of the salamander. Longer, wider enclosures should be chosen over higher, narrower enclosures. The bin should have 1-cm (0.5-inch) holes drilled in the lid for ventilation, or the center region of the lid can be cut out and fiberglass screen siliconed in place to prevent escapes. The use of the screen will allow visual checks of the animals without having to open the lid. The lid should be securely attached to the bin at all times to prevent the salamander from pushing the lid up and escaping. With larger animals, an enclosure at least 0.5 meters (1.5 feet) high is a good choice, as it prevents the salamander from routinely rubbing its snout on the lid while attempting to escape. The minimum depth of the water for these two species should be 10-15 cm (4-6 inches). The lids of plastic storage bins may be better than screen lids on aquaria. A large, active amphiuma may rub its snout on the screen if the screen lid covers the entire top of the enclosure.
If the goal is to attempt to reproduce the salamander in the long run, then an enclosure at least as wide and as long as the largest amphiuma to be housed in the tank is a good starting point. This tank should have multiple shelters on the bottom of the aquarium to allow each animal to choose its own hiding place. An easy method is to use PVC pipe that is as close as possible to the diameter of the amphiuma and as long as the largest amphiuma to be housed. There should be at least two pipes for each animal to allow each one to choose its own preferred hiding spot. Over this there should be maintained a thick layer of floating plants, and the aquarium should be well filtered preferably with a canister or other large filter. The returning current flow can be regulated by valves and a spray bar placed underwater.
Although filtration is not necessary, it reduces the need for frequent water changes and helps to maintain a stable water quality as bacteria that metabolize the waste products become established in the filter bed. Water changes should occur at a minimum of once a week in filtered enclosures, but may be necessary as often as once a day in unfiltered enclosures to remove shed skin and uneaten prey and prevent fouling of the enclosure. All of the water used for water changes should be dechlorinated and aged. Distilled, rainwater, and/or reverse osmosis water should only be used to replace evaporated water, as these sources of water lack sufficient ions and may cause calcium loss to the salamander. If the local tap water contains high amounts of minerals, then spring water can be used as an alternative. All filter equipment in the enclosure needs to be firmly secured to prevent the amphiuma from dislodging the intake or the outtake of the filter. The intake of the filter should be firmly covered to prevent entrapment and resulting injury or death.
These animals do not need heated enclosures, as they are all found in areas where the temperature can get well below 4.4°C (40°F). As an example, A. tridactylum is native to regions where the waterways can freeze over for weeks at a time. The temperature of the enclosures should not be allowed to rise above 26.7°C (80°F), as thermal stress may occur. Heating the tank may in fact be counterproductive, as this may prevent the salamanders from receiving thermal cues for reproduction.
Feeding :
In the wild, amphiumas eat nearly anything that they can catch, including various invertebrates such as worms, crustaceans, and snails. The two larger species also eat fish, frogs, salamanders, and even small snakes. A. pholeter in captivity does well on a diet of blackworms, but will also take small crickets, wax worms, small earthworms, and other small invertebrates. In captivity the two larger species will often accept some pelleted food, as well as small fish, frogs, tadpoles, crayfish, raw or cooked shrimp, and other prey items. Amphiumas will eat smaller salamanders, including conspecifics, so animals housed together should be of similar size. Long forceps or hemostat can be used to individually hand-feed animals to prevent injuries to each other from feeding responses. These injuries can occasionally be fatal. An alternative method for feeding is to maintain a small population of freshwater shrimp or crayfish in the aquarium at all times, both as a food source and as scavengers for uneaten food. This will allow the salamanders to feed as necessary to supplement hand-feeding.
Care must be taken to avoid being bitten. The bite of an amphiuma is said to be painful, though rarely of medical significance. There are reports of amphiuma bites requiring stitches. As a maintance diet, the salamanders should be fed to satiation once a week, but if the animals are being conditioned to attempt breeding, then multiple feedings each week may be necessary.
Breeding :
Internal fertilization occurs through the direct transfer of the spermatophore. The courtship and reproductive process in A. pholeter has not been recorded yet, and the understanding of courtship in A. means has large gaps in our knowledge. Reproduction of A. tridactylum is the best documented of the three species. In this species, males court a female by swimming around her in an elaborate spiral, sometimes in large groups. The females lay clutches of roughly 100 eggs in a burrow or under an object near the edge of water. The eggs are presumably laid under the water, but as the water level recedes, the eggs are exposed. Females are often found incubating or guarding the eggs. Oviposition is believed to mainly occur during the warm months, but hatching is most common in October and November, though it has been documented to occur as late as the following May. Incubation time is approximately 4-5 months (see Petranka 1998 for more information).
If captive breeding is to be attempted, then the animals should be exposed to a temperature drop and, later, an increase. Concurrently, there should be a decrease and then increase in the photoperiod.
Conservation :
There are no large scale breeding programs for these species, thus those that are available from supply companies are invariably wild caught. Though this trade does not appear to have an adverse impact on wild populations as a whole, care should be taken to not over-harvest these species. Breeding programs for these species should be developed to reduce or eliminate the potential risk to wild populations. As with most other animals, habitat destruction and possibly the introduction of exotic species are putting these interesting salamanders at risk throughout their range.
Origin : Mexico and USA (NC, SC, FL, GA, AL, AR, MS, LA, TX, OK, MO, TN, KY, IN, IL, MI)
Subspecies : S. i. intermedia , S. i. nettingi
IUCN : Red BookLeast concern
CITES : No listing
First described : Barnes, 1826 , (S. i. intermedia) Goin, 1942 (S. i. nettingi)
Lesser sirens are a large salamander with many neotonic traits, including exposed gill tufts throughout adult life. Lesser sirens lack hind limbs and have front limbs that have 4 toes on each foot. (In contrast, dwarf sirens, Pseudobranchus spp. have 3 toes on each foot, and the Amphiumas have 4 small legs.) Juvenile lesser sirens have red to yellow colors banding the head and (except for Siren i. intermedia) all have distinct stripes running down the body. As the siren grows older these patterns fade until the plainer adult coloration is reached. Sexually mature lesser sirens have a dorsal pattern that is usually an olive green to grayish blue or black. Some individuals may have scattered spots on the dorsal surface. The ventral surface is usually lighter in color, tending more towards a light gray color. Lesser sirens can range in size from 7 to 27 inches (17 - 69 cm) depending on the subspecies. There are 2 subspecies of lesser sirens recognized at this time, although research is indicating that there may be more species. They are the eastern Lesser Siren (Siren i. intermedia) and the Western Lesser Siren (S. i. nettingi). The easiest way to distinguish between the subspecies is to know the collection locality, otherwise costal groove counts and colors may give a clue to the identity.
Distribution and Habitat :
Lesser sirens range from North Carolina south to southern-central Florida, west to east and southern Texas and north from Texas in the Mississippi valley to Indiana and Illinois. Localized colonies may also be found in southeastern Virginia, northeastern North Carolina, southwestern Michigan, and northern Indiana. Lesser sirens can be found inhabiting the mud and debris that are located on the bottom of still and slow moving waters such as sloughs and ponds. The habitat doesn't necessarily need to be a permanent body of water. If the body of water temporarily dries up the sirens will burrow into the bottom and aestivate. Juveniles can aestivate for approximately 12 to 14 weeks before starving to death, while well-fed adults can aestivate for at least 16 weeks. In the wild lesser sirens feed upon snails, worms, aquatic invertebrates, and occasionally fish. However, while feeding a fair amount of aquatic vegetation is also ingested. The algae and vegetation tends to be poorly digested and may just be an artifact of the manner in which the sirens feed.
Conservation Status :
Until the number of species and subspecies has been finalized, the conservation status will be difficult to determine. However, habitat fragmentation may have a serious impact on the viability of this species.
Housing :
Housing should depend upon the size of the animal, with small juveniles housed in aquariums of 10 gallons (38 liters) or larger. Larger animals are housed in appropriately sized larger aquariums with a tight fitting lid. An adult S. i. intermedia can be comfortably housed in a 20 gallon long (76 liter) aquarium. An adult S. i. nettingi may require an aquarium as large as 40 gallons (151 liters).
The aquarium should be filtered with an appropriate sized canister or submersible filter. Avoid using a hang-on-tank filter, as gaps in the lid of the aquarium may permit escape. Water quality should be maintained through weekly 10-20% water changes, while more frequent changes are indicated if ammonia and/or nitrite is detected. The aquarium can be aquascaped with stones that are too large for the salamander to ingest, as well as with floating plants. Planting the aquarium is not really practical, as the siren will disrupt the plants during its evening activity. A shelter that the siren can hide inside or under should also be provided to help prevent stress. Appropriate shelters can be constructed from PVC pipe cut to length, pieces of drift wood, or rock shelters that have been siliconed together to provide stability. The siren will primarily be active during the evening and nighttime hours. However, lesser sirens will also learn a feeding schedule and become active around feeding time.
Lesser sirens do best when the enclosure temperature is maintained between 65-80°F (18-26°C) with a twice a week feeding to satiation in adults and daily feeding for juveniles. With juveniles, all uneaten food should be removed with 24 hours to prevent the aquarium from fouling. With good care, lesser sirens can live for more than 14 years in captivity.
Female S. i. intermedia. Contrast the head shape to the male below.
Male S. i. intermedia, showing enlarged masseter muscles that give males their characteristic head shape.
Feeding :
Once acclimated, lesser sirens are aggressive feeders. If more than one siren is housed in an aquarium, then hand feeding with tweezers may be necessary to prevent one siren from monopolizing the food supply. Juveniles can be fed on black worms, tubifex worms, daphnia, small snails, bloodworms, white worms and small red worms. As the siren grows, the size and amount of the food offered can be increased until the salamander is on the adult diet. Adult lesser sirens can be fed large earthworms, pinkie mice, small fish, and pieces of meat. However whole prey items are the best food items possible as this decreases the probability of dietary deficiencies. If fish are being used as part of the diet, then care should be taken to not feed an exclusive diet of fish. This can lead to thiamin deficiencies as well as fatty liver problems, which are most commonly associated with a diet of either frozen fish or goldfish.
S. i. intermedia breeding tank. It is a large tank with cold slowly flowing water.
S. i. intermedia eggs and hatchling.
Breeding :
Sexual maturity is usually reached in two to three years depending upon the population involved. Adult males can be identified by the enlarged masseter muscles causing the temporal region of the head to appear swollen.
During the breeding season, male lesser sirens may engage in biting behaviors. Spent females have been observed with multiple bites possibly indicating that biting is part of courtship in this salamander. Also, males have been observed with bite marks, indicating either mate guarding behaviors or territorial encounters. The breeding season is variable depending on geography, with the southern localities breeding earlier. Southern populations may start as early as December-March in central Florida and March to April in the Carolinas. The eggs are deposited primarily in large masses that may consist of several layers of eggs. The eggs are a dark brown color and have a sticky gel coat adhering to each other as well as to plants, twigs, and roots.
The egg mass may number between 200 and 700 eggs. The eggs hatch in 1.5 to 2.5 months, estimated based on the collection of newly hatched larvae in appropriate habitats. It is unclear if the sirens collected in the vicinity of the clutches are engaged in guarding the clutch or are incidental to the area, as appropriate habitats may have a very large population of these salamanders (up to 1.1 animal/square meter, Petranka; 1998). Lesser sirens have been collected with lesser siren eggs in their digestive tract. It is uncertain whether this is a female guarding a clutch and feeding on the eggs in her own clutch or other sirens predating upon egg clutches. It is unknown at this time if lesser sirens have internal or external fertilization of their eggs. Captive reproductions of this species have rarely been recorded. If breeding is to be attempted, the day length should be shortened while lowering the enclosure temperature.
Raffaelli reported a successful captive breeding in 2007. About 60 eggs produced, and about a dozen were fertile. The adults had been kept at 7-8°C (44-46°F), and the eggs were deposited under a rock in spring when the water temperature reached 12°C (54°F). Adult activity was observed under the rock, suggestive of external fertilization and/or parental care of the eggs. See References below for link to additional information.
