Anglers & Frogfish :
From Wikipedia, the free encyclopedia :
Frogfishes, family Antennariidae, are a type of anglerfish in the order Lophiiformes. They are known as anglerfishes in Australia, where 'frogfish' refers to the Batrachoididae. Frogfishes are found in almost all tropical and subtropical oceans and seas around the world, the primary exception being the Mediterranean Sea.
Frogfishes are small, short and stocky, and sometimes covered in spinules and other appendages to aid in camouflage. The camouflage aids in protection from predators and to enables them to lure prey. Many species can change colour; some are covered with other organisms such as algae or hydrozoa. In keeping with this camouflage, frogfishes typically move slowly, lying in wait for prey, and then striking extremely rapidly, in as little as 6 milliseconds.
There are few traces of frogfishes in the fossil record, though Antennarius monodi is known from theMiocene of Algeria.
Range :
Frogfishes live in the tropical and subtropical regions of the Atlantic and Pacific, as well as in the Indian Ocean and the Red Sea. Their habitat lies for the most part between the 20-degree isotherms, in areas where the surface level water usually has a temperature of 20 C (68 F) or more. They extend beyond the 20-degree isotherms in the area of the Azores, Madeira and the Canary Islands, along the Atlantic coast of the USA, on the south coast of Australia and the northern tip of New Zealand, coastal Japan, around Durban, South Africa and at Baja California, USA. The greatest diversity of species is in theIndo-Pacific region, with the highest concentration around Indonesia. In the small Lembeh Strait, north-east of Sulawesi, divers have found nine different species. Frogfish live generally on the ocean floor around coral or rock reefs, at most up to 100 metres (330 ft) deep.
There are a few exceptions to these general limits. The Brackishwater Frogfish is at home in ocean waters as well as brackish and fresh wateraround river mouths.The Sargassumfish lives in clumps of drifting sargassum, which often floats into the deeper ocean and have been known to take the sargassumfish as far north as Norway.
Features :
Frogfishes have a stocky appearance, atypical of fish. Ranging from 2.5–38 cm (1-15 inches) long, their plump, high-backed, non-streamlined body is scaleless and bare, often covered with bumpy, bifurcated spinules. Their short bodies have between 18 and 23 vertebrae and their mouths are upward pointed with palatal teeth. They are often brightly colored, white, yellow, red, green, or black or spotted in several colors in order to blend in with their coral surroundings. Coloration can also vary within one species, making it difficult to differentiate between them.
Rather than typical dorsal fins, the front-most of the three fins is called the illicium or "rod" and is topped with the esca or "lure". The illicium often has striped markings, while the esca takes a different form in each species. Because of the variety of colours even within a single species, the esca and illicium is a useful tool to differentiate among different varieties. Some of them resemble fish, some shrimp, somepolychaetes, some tubeworms and some simply a formless lump; one genus, Echinophryne has no esca at all. Despite very specific mimicry in the esca, examinations of stomach contents do not reveal any specialized predation patterns, for example, only worm-eating fish consumed by frogfishes with worm-mimicking esca. If lost, the esca can be regenerated. In many species the illicium and esca can be withdrawn into a depression between the second and third dorsal fins for protection when they are not needed.
Frogfish have small, round gill openings behind their pectoral fins. With the exception of Butler's frogfishand the Rough Anglerfish, frogfish use a gas bladder to control their buoyancy.
A striated frogfish, with upturned mouth, very distinct spinules, and esca in the form of a white worm
Mimicry and camouflage :
The unusual appearance of the frogfish is designed to conceal it from predators and sometimes to mimic a potential meal to its prey. Inethology, the study of animal behavior, this is known as aggressive mimicry. Their unusual shape, colour and skin textures disguise frogfish. Some resemble stones or coral, while others imitate sponges, or sea squirts with dark splotches instead of holes. In 2005, a species was discovered, the striated frogfish, that mimics a sea urchin while the sargassumfish is coloured to blend in with the surrounding sargassum. Some frogfish are covered with algae or hydrozoa. Their camouflagecan be so perfect, that sea slugs have been known to crawl over the fish without recognizing them.
For the scaleless and unprotected frogfish, camouflage is an important defense against predators. Some species can also inflate themselves, like pufferfish, by sucking in water in a threat display. In aquariums and in nature, frogfish have been observed, when flushed from their hiding spots and clearly visible, to be attacked byclownfish, damselfish, and wrasse, and in aquariums, to be killed.
Many frogfishes can change their colour. The light colours are generally yellows or yellow-browns while the darker are green, black or dark red. They usually appear with the lighter color, but the change can last anywhere from a few days to several weeks. It is unknown what triggers the change.
A frogfish disguised as an alga-covered stone..
A Frogfish in Mactan, Philippines..
Movement :
Frogfishes generally do not move very much, preferring to lie on the sea floor and wait for prey to approach. Once the prey is spotted, they can approach slowly using their pectoral and pelvic fins to walk along the floor. They rarely swim, preferring to clamber over the sea bottom with their fins in one of two "gaits". In the first they alternately move their pectoral fins forward, propelling themselves somewhat like a two-legged tetrapod, leaving the pelvic fins out. Alternately, they can move in something like a slow gallop, whereby they move their pectoral fins simultaneously forward and back, transferring their weight to the pelvic fins while moving the pectorals forward. With either gait, they can only cover short stretches.
In open water, frogfishes can swim with strokes of the tail fin. They also have a kind of jet propulsion that is often used by younger frogfish. It is achieved by rhythmically forcing their breath-water out through their gill openings, which lie behind their pelvic fins.
The sargassum frogfish has adapted fins which can grab strands of sargassum, enabling it to "climb" through the seaweed.
Hunting :
Frogfishes eat crustaceans, other fish, and even each other. When potential prey is first spotted, the frogfish follows it with its eyes. Then, when it approaches within roughly seven body-lengths, the frogfish begins to move its illicium in such a way that the esca mimics the motions of the animal it resembles. As the prey approaches, the frogfish slowly moves to prepare for its attack; sometimes this involves approaching the prey or "stalking" while sometimes it is simply adjusting its mouth angle. The catch itself is made by the sudden opening of the jaws, which enlarges the volume of the mouth cavity up to twelve-fold, pulling the prey into the mouth along with water. The attack can be as fast as 6 milliseconds. The water flows out through the gills, while the prey is swallowed and the esophagus closed with a special muscle to keep the victim from escaping. In addition to expanding their mouths, frogfish can also expand their stomachs to swallow animals up to twice their size.
Slow-motion filming has shown that the frogfish sucks in its prey in just six milliseconds, so fast that other animals cannot see it happen. This is less time than it takes a muscle to contract, so the source of the motion remains unknown.
A spotfin frogfish waiting amid the coral
Reproduction :
The reproductive behavior of the normally solitary frogfish is still not fully researched. There are few observations in aquariums and even fewer from the wild. Most species are free-spawning, with females laying the eggs in the water and males coming in behind to fertilize them. Anywhere from eight hours to several days before the egg-laying, the abdomen of the female starts to swell as the eggs absorb water, sometimes as many as 180,000 eggs. The male begins to approach the female around two days before the spawning. It is not known if the spawn is predetermined by some external factor, such as the phase of the moon, or if the male is attracted to a smell or signal released by the female. In all hitherto observed breeding pairs, one partner was noticeably, sometimes as much as ten times, larger than the other. When the gender could be determined, the larger partner was always the female.
During the free-spawning courtship ritual, the male swims beside and somewhat behind the female, nudges her with his mouth then remains near her cloaca. Just before the spawning, the female begins to swim above the ocean floor toward the surface. At the highest point of their swim they release the eggs and sperm before descending back. Sometimes the male pulls the eggs out of the female with his mouth. After mating the partners depart quickly as otherwise the smaller male would likely be eaten. A few species are substrate-spawners, notably the generaLophiocharon, Phyllophryne and Rhycherus, which lay their eggs on a solid surface, such as a plant or rock. Some species guard their eggs, a duty assigned to the male in almost all species, while most others do not. Several species practice brood carrying, for example the three-spot frogfish, whose eggs are attached to the male, and those in the genus Histiophryne, whose brood are carried in the pectoral fins.
The eggs are 0.5-1mm (0.02-0.04in) large and cohere in a gelatinous mass or long ribbon, which in Sargassumfish are up to a metre (3.3 ft) long and 16 cm (6 in) wide. These egg masses can include up to 180,000 eggs. For most species, the eggs drift on the surface. After two to five days, the fish hatch and the newly hatched alevin are between 0.8 and 1.6 mm long (0.03 and 0.07 in). For the first few days they live on the yolk sac while their digestive systems continue to develop. The young have long fin filaments and can resemble tiny, tentacled jellyfish. For one to two months they live planktonically. After this stage, at a length of between 15 and 28 mm (0.6-1.1 in), they have the form of adult frogfish and begin their lives on the sea floor. Young frogfish often mimic the coloration of poisonous sea slugs or flatworms.
Fossil record :
Hardly any fossil remains of frogfishes have been found. In the north-Italian formation at Monte Bolca, formed from the sedimentation of theTethys Ocean in the middle Eocene, a three centimeter (1.2 in) fossil named Histionotophorus bassani was initially described as a frogfish, but was later thought to belong to the closely related extant genus Brachionichthys or handfish. In 2005, a fossil from Miocene Algeria, Antennarius monodi, is the first proven fossil frogfish, believed to be most closely related to the extant senegalese frogfish.
In aquariums :
Many public aquariums around the world keep frogfishes. Although prized for their unique appearance, they are not easy to keep for a number of reasons. They often refuse food or become very fat when they do accept it. Also, they must usually be kept alone as they will eat anything up to twice their size, including other frogfish including potential mates. Also, as they can change their coloration, many lose the bright patterns they have initially, especially when kept in empty or more dull-colored tanks as opposed to the bright coral environments that they are used to.
Though frogfish have been observed to spawn in captivity, captive breeding is difficult. It is currently not known how to sex most species without dissection so keeping an appropriate pair together raises problems. Furthermore even if they do spawn, raising fry through the planktonic phase is very difficult because the larval fish require extremely tiny live food and must be protected from other predatory fish.
Taxonomy:
Frogfishes belong to the order Lophiiformes, commonly known as anglerfish, which is a member of the superorder Paracanthopterygii with four other orders. They belong to the infraclass Teleostei, the bony fishes, in the class Actinopterygii.
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The female striated frogfish does not tolerate the smaller male after fertilisation, and may eat him if he stays close ..Striated frogfish mating - YouTube
Frog fish suitable for Aquarium :
1- Assorted Angler (Antennarius sp.) :
Minimum Tank Size: 30 gallons
Care Level: Moderate
Temperament: Semi-aggressive
Reef Compatible: With Caution
Water Conditions: 72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.020-1.025
Max. Size: 9"
Color Form: Black, Tan, Yellow
Diet: Carnivore
Compatibility: View Chart
Origin: Africa, Caribbean, Fiji, Indonesia, Mexico
Family: Antennariidae
General Requirement for keeping in Aquarium :
Origin: Indo-Pacific & Caribbean
Tank Temperature: 75-82°F
pH: pH 8.0-8.4
Specific Gravity: 1.020-1.024
Feeding:
Carnivorous; may not take frozen food right away; may need to be fed live foods, like shrimp, mollies or other crustaceans; feed 2-3 times a week
Behavior:
Ambush predator; hides in rockwork until potential prey approaches; will eat tankmates up to their own size; does not move much, tends to hover or "walk" instead of swimming actively
Compatibility:
Reef Safe; not invert safe (won't harm corals and stationary inverts like feather dusters but may eat smaller shrimp, crabs, and other crustaceans); can be kept with other fish that are larger; do not keep with aggressive fish.
Anglers & Frogfish are bizarre and interesting reef compatible fish. These ambush predators come in a variety of colors and patterns that allow them to blend perfectly into their reef environment.
They also have a fleshy, specialized appendage (the esca) that extends from the front portion of the dorsal fin. This appendage can be moved and bobbed to lure unsuspecting prey close enough to be gulped down. Frogfish have jaws made of thin and flexible bones that allow them to swallow large prey, and large expandable stomachs. These adaptations make it possible for them to swallow and digest prey as big as their own body!
Anglers & Frogfish can grow to be as large as 8 inches depending on the species. The largest species are the Giant Frogfish (Antennarius commersoni), the Shaggy Anglerfish (A. hispidus), and the Patterned Anglerfish (Antennarius sp.). Smaller species, such as the Warty Anglerfish (A. maculatus) only grow to be about 4 inches long.
The Assorted Anglers can range in color from tan to grey to brown. Their body can also change color to blend with the surrounding environment over time. They require large amounts of live rock in a 30 gallon or larger aquarium.
When first introduced into the aquarium, live saltwater feeder shrimp should be used to entice this fish to eat. An angler may eat any small inhabitant of the tank (crustacean or fish) that is lured into its mouth with the use of an esca (modified first dorsal spine) that looks like a small, tasty fish. It will accept most meaty meals including feeder fish and shrimp.
Approximate Purchase Size: Small: 1" to 2"; Medium: 2" to 4"; Large: 4" to 6"; X Large 6" to 7"; XX Large 7" to 8"; Show Size 8" to 9"
2-Wartskin Angler
Antennarius maculatus
Minimum Tank Size: 20 gallons
Care Level: Moderate
Temperament: Peaceful
Reef Compatible: With Caution
Water Conditions: 72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.020-1.025
Max. Size: 4"
Color Form: Pink, White, Yellow
Diet: Carnivore
Compatibility: View Chart
Origin: Indonesia, Vanuatu
Family: Antennariidae
Also referred to as the Warty Frogfish or Wartskin Frogfish, the Wartskin Angler is aptly named, looking more like a rock or piece of coral. The Wartskin's colors can vary widely, from browns to reds, yellows to purples and white. It also has the chameleonic ability of changing color to blend with its surroundings.
A good reef dweller, the Wartskin enjoys perching on coral ledges and requires a tank of at least 20 gallons. The Wartskin Angler is a hardy aquarium member but not recommended for beginners.
The Wartskin feeds by ambush, lying in wait for an unsuspecting fish or crustacean to go by and then lunging forward, grabbing and swallowing the victim whole. The Wartskin has been known to devour fish nearly equal to its own size.
When first introduced into the aquarium, live saltwater feeder shrimp should be used to entice this fish to eat. The Wartskin Angler should be given feeder fish and shrimp, but do not overfeed as the Wartskin may stop feeding.
Approximate Purchase Size: Tiny: 3/4" to 1-1/4" Small: 1-1/4" to 2"; Medium: 2" to 3" Large: 3" to 4"
3-Red/Orange Angler
Antennarius sp.
Minimum Tank Size: 20 gallons
Care Level: Moderate
Temperament: Semi-aggressive
Reef Compatible: With Caution
Water Conditions: 72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.020-1.025
Max. Size: 6"
Color Form: Black, Orange, Red
Diet: Carnivore
Compatibility: View Chart
Origin: Africa, Indonesia, South Asia
Family: Antennariidae
The Colored Anglers can range in color from a vivid red to a deep orange coloration. Their body can also change color to blend with the surrounding environment over time. They require large amounts of live rock in a 20 gallon or larger aquarium.
When first introduced into the aquarium, live saltwater feeder shrimp should be used to entice this fish to eat. An angler may eat any small inhabitant of the tank (crustacean or fish) that is lured into its mouth with the use of an esca (modified first dorsal spine) that looks like a small, tasty fish. It will accept most meaty meals including feeder fish.
Approximate Purchase Size: Small: 1" to 2" Medium: 2" to 3" Large: 3" to 5"
4-Striated Angler
Antennarius striatus
Minimum Tank Size: 30 gallons
Care Level: Easy
Temperament: Peaceful
Reef Compatible: With Caution
Water Conditions: dKH 8-12, pH 8.1-8.4, sg 1.020-1.025, 65-75° F
Max. Size: 8½"
Color Form: Tan
Diet: Carnivore
Compatibility: View Chart
Origin: South China Sea, Sri Lanka
Family: Antennariidae
The Striated Angler Fish, also known as the Striped Anglerfish, is a member of the Antennariidae family. With a body of striped brown and tan, several projections give it more of an ornate rock-like appearance than that of a fish. These fish will alter its color to blend into its background, as can be seen in the above photo.
A good reef dweller, the Striated Angler Fish enjoys perching on coral ledges and requires a tank of at least 30 gallons.
The Striated Angler Fish feeds by ambush, lying in wait for an unsuspecting fish or crustacean to go by and then lunging forward, grabbing and swallowing the victim whole. The Striated Angler Fish has been known to devour fish nearly equal to its own size.
When first introduced into the aquarium, live saltwater feeder shrimp should be used to entice this fish to eat. A diet of feeder fish and shrimp should be provided. Do not overfeed as the Striated Angler Fish may stop feeding.
Approximate Purchase Size: Small: 1" to 2"; Medium: 2" to 4"
5-Sargassum Fish
Histrio histrio
Minimum Tank Size: 30 gallons
Care Level: Moderate
Temperament: Peaceful
Reef Compatible: Yes
Water Conditions: 72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.020-1.025
Max. Size: 6"
Color Form: Tan
Diet: Carnivore
Compatibility: View Chart
Origin: Indian Ocean
Family: Antennariidae
The Sargassum Fish is a member of the Antennariidae family. With a body of mottled brown and tan, several projections give it more of an ornate rock-like appearance than that of a fish.
A good reef dweller, the Sargassum enjoys perching on coral ledges and requires a tank of at least 30 gallons.
The Sargassum feeds by ambush, lying in wait for an unsuspecting fish or crustacean to go by and then lunging forward, grabbing and swallowing the victim whole. The Sargassum has been known to devour fish nearly equal to its own size.
A diet of feeder fish and shrimp should be provided. Do not overfeed as the Sargassum may stop feeding.
Approximate Purchase Size: Small: 1" to 2"; Medium: 2" to 3"; Large: 3" to 5"
