Scorpaena brasiliensis in a home aquarium. From this photo it should be obvious why Scorpionfish can swallow prey over 1/2 their size. Photo courtesy of Chris Smallridge.
Scorpionfish: Masters of Camouflage
courtesy to : www.reefkeeping.com
Continuing the theme of the November issue on venomous fishes, I'll be discussing a portion of the family Scorpaenidae. Also called Scorpionfish, these deadly predators make fantastic displays in small aquariums dedicated to their care. However, keeping these unusual fish is not in the best interest of most hobbyists, as I hope to make clear in this month's column.
Meet the Family
Scorpaenids are well represented throughout the world's oceans; however, relatively few species are located within the warmer water areas, which supply most of the marine ornamental fish for aquarists. For information on some of the many scorpaeonids found in cooler waters, see this month's columnby Dr. Ron Shimek. Nearly 400 species comprise the family, divided amongst the 45 genera (Eschmeyer, 1986). Most important to hobbyists are the Scorpionfishes, Devilfishes, and Stonefishes. Lionfishes are in a subdivision of the family Scorpaenidae, the subfamily Pteroinae. For information on the care of Lionfishes, please click here
All Scorpaenids are equipped with a large mouth, capable of swallowing prey over half their own body length. Spines are present on the gill plate and head, though these are not the spines hobbyists need to be concerned about. The thick dorsal, pelvic, and anal spines should gather the attention of the caretaker, as these are the spines capable of delivering a powerful, painful, and possibly deadly sting.
Scorpions :
Many Scorpaenids have the ability to shed the outermost skin layer, the cuticle. Because of their sedentary lifestyle, it is not uncommon for algae or other pests to grow on these fish. The shedding benefits the fish by removing any attached algae, cyanobacteria, and even parasites. There does not appear to be a set schedule to the behavior, though we know some Scorpaenids shed more often than others (Eschmeyer, 1986).
In the Wild:
As the title of this column implies, many Scorpaenids, particularly the Scorpionfishes, have a remarkable ability to blend into their surroundings. One advantage to their camouflage is that it assists in prey capture. Often, herbivorous prey will be attracted to the Scorpionfish and their encrusting algae. Other times, the encrusting algae can appear to be a "safe-haven" to passing-by fish and crustaceans. Regardless of the attraction, it is often a fatal one. The unfortunate prey rarely has a warning, as the attack of the Scorpionfish is lighting fast. The Scorpionfish creates a vacuum by quickly opening their jaws, sucking the prey into the awaiting mouth of the predator. Individuals within one genus of Scorpaenids, the Stonefish, have been reported to complete the vacuum-style attack in as little as 15 milliseconds (Michael, 1998).
Scorpionfish habitat varies greatly amongst species according to the camouflage. As examples, some members are best suited to mud bottoms, while others have camouflage that renders them unnoticeable amongst Pocillopora spp. corals. Generally speaking, for any given terrain in the shallow-water tropical oceans, one or more Scorpionfish have adapted to it and perfected the art of camouflage within it.
Scorpionfish are generally solitary in nature, except during courting and mating when a pair may be located. Groups larger than a pair are rarely found. An exception to this is found in the Leaf Scorpionfish, which commonly occurs in groups of three. Fighting does occur between conspecifics, though scientists are not sure if they are defending their territory or their mates.
Like many venomous animals, Scorpionfish may have brilliant color warning. However, unlike many venomous animals these colors are not on permanent display. After all, such a display would make their camouflage pointless. Using a behavior known as "flashing," many Scorpionfish have the ability to display their colors when needed, such as when a predator is nearby. Their colors are often found on the inner surface of their pectoral fins. Some species also have brilliant colors on the skin within their jaw structure that can be exposed when the fish opens its mouth. This serves as an effective warning defense for approaching conspecifics.
In the Home Aquarium
Captive care of Scorpionfish is rather easy, assuming the hobbyist meets a few basic requirements. First and foremost is feeding. Often, live foods will be required to entice newcomers to eat in a captive environment. Although commonly employed as a suitable live food source, frequent feedings of goldfish should be avoided. A diet of goldfish tends to lead to a thiamin deficiency in Scorpionfish, which often results in death from loss of nervous system coordination. Other complications derived from a steady diet of goldfish are a lack of marine-based HUFA, excessive fat, and ammonia toxicity (Marini, pers. comm.). Instead, the hobbyist should concentrate their efforts on getting a recently acquired Scorpionfish to accept prepared foods. Knowing the natural foods of a particular species is the first step in proper nutrition, and in finding suitable prepared food substitutes. Some Scorpionfish eat strictly fish, while others may eat only shrimp or crabs. Still others may accept just about anything that moves. Saltwater "silversides" maybe the best substitute for those requiring fish prey, while prawns are obviously the first choice for those that prefer shrimp. Initially, efforts to dupe the Scorpionfish into believing that the prepared foods are actually alive is the difficult part. The method most commonly used is to impale the dead fish or shrimp on a stick of some sort, such as a chopstick, rigid airline tubes, or thin acrylic rods. The next step is for the hobbyist to do his/her best job of making the prepared food appear alive by shaking or wiggling the stick that the food is impaled upon near the Scorpionfish. When feeding attempts during the day fail, try feeding at night. Most Scorpaenids are nocturnal, so feeding at night will be more natural.
Rhinopias eschmeyeri, possibly the plainest Rhinopias sp. having almost a complete lack of body camouflage. They can be found in light blue, yellow, orange, red, and even lilac color variations. Photo courtesy of Frank Marini.
The proper sized aquarium to house Scorpionfish does not need to be large. Some of the smaller members of the family can be housed in a 20 gallon tank, while a 75 gallon would do an adequate job of housing one of the larger species of Scorpionfish, or possibly several smaller Scorpionfish. More important than the overall size is the decoration used to recreate or simulate their natural habitat. A hobbyist considering a scorpionfish should research the habitat requirements for that species. Some will require plenty of caves, while others will require an open sandbed or even mud.
Very few tankmates can co-exist with Scorpionfish because most will be considered food. Less commonly, some fish may confuse the Scorpionfish with food of their own. Surgeonfish, Rabbitfish, and even Angelfish may occasionally pester Scorpionfish, mistaking the fish for algae or even sponges. Scorpionfish may also be a problem in a tank with corals. Due to their sedentary lifestyle, it is possible that a Scorpionfish may choose a particular coral as a prime territory and the continued presence of the fish may cause injury or death to the coral.
Compatibility chart for members of the family Scorpaenidae:
Note: While many of the fish listed are good tank mates for Scorpaenids, investigation should be done to assure peaceable co-existence. Additionally, some of the fish mentioned above are better left in the ocean or for advanced aquarists.
Almost as important for the success of scorpionfish in an aquarium as the captive care requirements is that hobbyists find enjoyment in the care of Scorpionfish. Hobbyists searching for an active fish, brightly-colored "showstoppers" or desiring a tank filled with other fish, shrimps, or crabs should skip this family of fish. In contrast, the hobbyist looking for unusual fish will enjoy keeping fishes from this group. However, because these fish are venomous and potentially dangerous, they must be considered carefully before purchase. I recommend that hobbyists with allergies to bee stings and those with children or other people that may put their hands in the tank for whatever reason avoid keeping any Scorpaenid fish.
Captive Reproduction
Captive reproduction of Scorpionfish has not yet been reported to date, and breeding attempts have been unsuccessful. In fact, very little is known about their reproduction in the wild. For most Scorpaenidae, fertilization of the eggs occurs outside the female body, often times in a large, floating, and gelatinous mass (Coral Realm). Prior to the fertilization, a short mating dance occurs which involves non-destructive fin nipping, gill cover flaring, and side-to-side rocking, Often, the male's color will intensify. Mated pairs are not monogamous (Marini, pers. comm.).
Meet the Species
Most of the Scorpionfish that are regularly available to the hobby are part of the subfamily Scorpaeninae. Within this subfamily are roughly 15 genera, and possibly over 150 species. The genusTaenianotus, or the Leaf Scorpionfishes, including the popular Taenianotus triacanthusare, are potentially suitable species for aquariums for several reasons. First, they can be housed in very small aquariums, a 20 or 30 gallon tank can adequately hold a pair or trio of these fish which are usually less than four inches in length. Second, they usually like to perch on rocks or caves out in the open and can thus be observed easily by aquarists. Third, they come in a virtual rainbow of colors: red, maroon, pink, yellow, tan, brown, and even black specimens are available. The difficulty in keeping these fish, as with other family members, is getting them to accept appropriate prepared foods. The hobbyist should start with live ghost shrimp, and slowly wean them to frozen/thawed Mysis shrimp, if possible.
Taenianotus tricanthus, a yellow variant is pictured here. These fish do best when housed in pairs or even trios. Care should be taken to keep water flow to a minimum, as it prefers areas protected from currents. Photo courtesy of Jeff Rosenfeld of The Vibrant Sea.
Another popular species for the aquarium trade is Scorpaena brasillensis, or the Orange Scorpionfish. Don't let the common name mislead you; they come in several colors, including orange, yellow, red, and brown. They can become large, reaching over 9" in length. Their main prey in the wild is shrimp and various other crustaceans, and usually they have no problem accepting this in the home aquarium, but they do accept prepared fish in the captive environment if the hobbyist has trouble locating other foods. They are best housed in aquariums 30 gallons or larger containing plenty of hiding spaces as well as macro algae, as they are most often encountered in the wild in front of, or on, patches of macro algae.
Scorpaena brasiliensis is common around the tropical coast of the USA, and is probably the most common Scorpionfish found in the hobby. Photos courtesy of Frank Marini.
Some of the stranger Scorpaenidae are the Seagoblins, Inimicus species. This genus comes from one of the subfamilies of Scorpaenidae, the Choridactylinae. Two major differences separate them from the rest of Scorpaenidae. First, they have two pectoral rays that have the appearance of claws. Second, they have eyes that rest very high on the head. Both of these differences aid the fish in capturing prey. Individuals of Inimicus species like to bury themselves in sand or mud (and thus an open sandbed or mud should be provided deep enough so the fish can bury into it) with only their eyes, dorsal fin, and two front pectoral rays exposed. The eyes, being located high on the head, allow it to bury deeper, and the "claws" assist in lunging forward to capture the prey. In the aquarium, these fish adapt to prepared food fairly well and can initially be coaxed to feed on ghost shrimp, later weaned onto thawed Mysisshrimp, and finally onto various other prepared foods. If the fish are healthy, they fare reasonably well in the home aquarium, but be aware that they are often harassed by other fish that view their tassled flesh as potential food. Much like wrasses in the genus Macropharyngodon, Seagoblins have a tendency to be injured during shipping. The lack of sand in the shipping bags causes undo stress to the fish, and, as a result, they usually injure their lower jaw during shipping. Shipping with an inch or two of sand would allow the fish to bury themselves and thus help eliminate stress, and the subsequent damage caused by the undue stress. Be cautious and inspect the lower jaw when purchasing.
Inimicus didactylus in a home aquarium. Note the large eyes located high up on the head, and the two rays that look simliar to claws. Also notice the up-turned mouth. All of these attributes aid in capturing prey when buried underneath an inch or two of sand. Photo courtesy of Frank Marini.
Another photo of Inimicus didactylus. This time note the pelvic fin on the right. Though not fully opened, you can begin to see the coloration within the fin that allows it to "flash" for defense. Photo courtesy of Frank Marini.
A nice shot of the exposed venomous dorsal spine on Inimicus didactylus. Photo courtesy of Frank Marini.
Choridactylus sp. giving us a great view of the two pectoral rays used in crawling along the sandbed or for capturing prey. Photo courtesy of Frank Marini.
For the collectors of rare and extremely expensive fish, individuals of the various Rhinopias species, also in the subfamily Scorpaeinae, are sometimes available. Hobbyists that are willing to pay the $2000 US price tag for these fish are then owners of some of the most exotic looking fish on the planet. Their dermal appendages are amongst the most extravagant of all marine fish, rivaling only the Ghost pipefish of the family Solenostomidae. Care for them is extremely similar to that required for other Scorpionfish. In fact, they often adapt to prepared foods easier than some other Scorpaenids. Most Rhinopias species live within or near macro algae, and will make a faster transition to aquariums containing macros.
The extremely rare and beautiful Rhinopias aphanes. Would you pay $2000+ for this fish? Photos courtesy of Dustin Dorton of Aquarium City.
Close relatives of the Scorpionfish, and often considered as members of that family, are the Waspfish. They were, in fact, originally classified as the subfamily Apistinae of the family Scorpaenidae. They have since been elevated to the family Terrarogidae. This family contains 11 genera and 35 species. Although they are not regularly imported for the aquarium trade, the care of these species is similar to that required for the true Scorpaenidae. As adults, they barely reach 3" in length, and spend the majority of their time amongst macroalgae and sponges. Their main diet consists of worms, small fish, and even small crustaceans. Like Scorpionfish, Waspfish are primarily nocturnal, and offering food at night may encourage a feeding response, if required.
Note the white patch on the face of Paracentropogon longispinus. This white face is common amongst Paracentropogon spp. These little devils can be found on mud flats from south Australia to the Philipines. Photo courtesy of Frank Marini.
In Conclusion :
For those hobbyists looking to obtain the odd fish, Scorpionfish may fit your desires. Their hardy nature, small tank requirements, and ability to resist most diseases make them great choices for species-only aquariums and newcomers to the hobby. However, please use caution when handling these fish, or when working in their tank. One mistake will be painful, if not deadly.
Scorpions species list ( normally available in the markets ) :
The size of these fish varies, but most members reach an average length of seven inches in captivity. Scorpions are hardy fish that adapt well to life in captivity. They usually prefer live foods, but some species convert to frozen foods quickly especially when young. Provide these fish with ample hiding places and an appropriately sized aquarium for the species.
1-Leaf Fish
Taenianotus triacanthus
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: 4"
Color Form: Blue, Red, Tan, Yellow
Venomous: Yes
Diet: Carnivore
Compatibility: View Chart
Origin: Hawaii, Indonesia, Maldives
Family: Scropaenidae
The color of the Leaf Fish, also known as the Leaf Scorpionfish, or Paper Fish, varies between red, yellow, brown, or blue.
A 30 gallon or larger aquarium with live rock is suitable for this fish. It uses the live rock for hiding as well as for perching while looking for food. Tank mates should be passive fish including other Leaf Fish. It has poison glands attached to the dorsal, anal, and pelvic spines.
When first introduced into the aquarium, live saltwater feeder shrimp should be used to entice this fish to eat. The Leaf Fish diet consists of live foods such as feeder fish or small shrimp.
Approximate Purchase Size: Small; 1-1/2" to 2" Medium; 2" to 3" Large; 3" to 4"
Leaf Scorpionfish - Taenianotus triacanthus
Courtesy to : www.advancedaquarist.com By Pavaphon Supanantananont
The leaf scorpionfish is a reef safe fish that can be kept in reef tank with no harm to corals. But it is a threat to mobile inverts like shrimps and crabs, including much smaller fishes. It is best kept in peaceful community tank or a small reef tank that does not contains aggressive or picky fishes like triggers and Butterflyfish.
Family Scorpaenidae or the scorpionfishes are well known for their weird looking shape with the venomous spine to protect themselves from predators. But there was one scorpionfish that does not look “weird” or “spiny” as are the other members of the family. And yes, I am talking about the Leaf Scorpionfish (Taenianotus triacanthus).
The Leaf Scorpionfish is of Monotypic Genus, consisting of only one species, widely distributed in Indo-Pacific Region. It could be found from East Africa to Galapagos Island, as north as southern Japan to French - Polynesia and as south as Australia. They are found in pairs, but sometimes also observed singly or in a small group at depths from 1-134 meters. They are also known as Paper fish, Leaf fish, or flat Scorpionfish, due to their deep compressed body.
In the aquarium, these fish demonstrate similar behavior as in nature. They do not hide secretly in a dark place waiting for the prey to pass by and quickly dash toward the prey before sucking them into their stomach like other scorpions, but instead they perch on a well chosen position. It might be underneath the coral or some rockwork where the water current flows swiftly, even though in front of the tank or a bright area. The leaf scorpion use their “unique” sitting action, and bend their head lower than tail, move themselves side to side as if imitating a leaf moving by the water current. By this way, the prey will think that they were only a leaf and when the prey came to a place close enough, they will gasp the prey and eat it immediately.
I was attracted to the shape of this fish since I firstly saw them in a book and fell in love with their action at first sight. They don’t look too weird, but still, don’t look like normal fish. To me, it is more like a piece of a leaf or a trash than a fish. It appears in various colors: pink, white, marble, orange, and etc. I’ve been keeping three of the yellow phrase in one tank and they are doing well. A few months later, I got two 3” bright pink specimens imported from the Philippines. My friend asked one from me. I put the only one left in my invert tank together with corals and many smaller fish (which were not very small).
There I kept him with smaller, but faster fish like Adorn wrasse (Cirrhilabrus adornatus), Bicolor Anthias (Pseudanthias bicolor), Flame Hawkfish (Neocirrhites armatus), and the dwarf scorpion like the yellow spotted scorpionfish (Sebastapistes cyanostigma. All the fish were similar in size or a bit bigger. The leaf scorpionfish seems to show no interest in a bigger size prey. They do take time before pursuing their food, apparently checking to see that it could fit in its mouth.
The pink leaf scorpionfish was doing well for about two weeks in my tank, then it started to have a problem. In one evening, I noticed that its color was fading. But I think that it was only a small color change which might happen from stress or the changing of the environment. However, on the next day it was still fading, and turned completely yellow on the third day. I don’t know that this phenomenon could happen to all the colorful leaf fish in captivity, but the pink one that my friend got at the same time did not change its color like mine.
This leaf-like creature is not a finicky eater. They might require a living food such as mollies, guppies, or a small shrimp at first. But as they do acclimatize, they can be switched to a piece of cut seafood frozen or otherwise. Be careful when feeding these fish, try to place the prey in front of them so that it could easily be seen and do not overfeed them. Don’t feed them large amounts, keeping in mind that they do not need the amount of food as in nature.
Like few soft-skin scorpionfish such as the Rhinopias sp., the leaf scorpionfish also shade their skin cuticle like molting once or twice a month. Before that the fish will show less interest in food, but it will turn back to its normal habits and the color will be stronger after its shading. The soft water current will help them to release their molt easier. The slimy molt will be appeared in transparent form, floating in the tank or sticking to something in the tank and should be taken out if seen.
It is a reef safe fish that can be kept in reef tank with no harm to corals. But it is a threat to mobile inverts like shrimps and crabs, including much smaller fishes. It is best kept in peaceful community tank or a small reef tank that does not contains aggressive or picky fishes like triggers and Butterflyfish. Good tank mates are lionfish, squirrelfish, etc. Beware that these fish get to eat enough if housed with more aggressive mates. They do attain to the maximum size of 10 cm. in captivity, but they could grow as big as 13 cm. in the wild. Anyway, their size is not too big for a home aquarium and it’s definitely a great display animal.
Note! Beware! It also has venomous spines like the scorpions do, so handle them with care!
References:
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Kuiter, R. H., 2005.- Guide to Sea Fishes of Australia, A comprehensive reference for divers & fisherman. New Holland Publishers, Australia. 434 pp.
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Lieske, E and R. Myers. 1994. Periplus Nature Guides. Reef Fishes of the world. Periplus Editions, Hong Kong. 400 pp.
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Michael, S., 1998. -Reef Fishes, Volume 1. TFH-Microcosm, USA. 624pp.
2-Orangebanded Stingfish
Choridactylus multibarbus
Minimum Tank Size: 50 gallons
Care Level: Moderate
Temperament: Aggressive
Reef Compatible: No
Water Conditions: 72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.020-1.025
Max. Size: 5"
Color Form: Orange, Tan
Venomous: Yes
Diet: Carnivore
Compatibility: View Chart
Origin: Indonesia, Maldives
Family: Scorpaenidae
Hobbyists looking for an envy-inducing oddball for the venomous aquarium will find a truly unique specimen in the Orangebanded Stingfish.
Able to bury itself in ambush up to its high-set eyes, what truly sets this well-camouflaged fish apart are its pectoral rays which resemble "claws." The Orangebanded Stingfish uses these for both prey capture and locomotion across the muddy sea floor.
Provide a 50-gallon or larger aquarium with enough substrate for the Orangebanded Stingfish to bury itself. Since they are carnivorous hunters, only house with other fish that won't make tempting prey for their large vacuum-like mouths.
Choridactylus multibarbus is known to adapt to prepared foods fairly well. Begin with live ghost shrimp and wean to frozen/thawed mysis shrimp.
Dorsal, pelvic, and anal spines should be avoided as they are capable of delivering a painful and potentially harmful sting.
Approximate Purchase Size: Small 1" - 2" Medium 2" - 3" Large 3" - 4"
The Rhinopias Spp. – The Ultimate Scorpionfishes
courtesy to : www.advancedaquarist.com By Scott Michael
Of course, these piscine jewels command big bucks! But if you are really in to the odd and want to display a fish in your aquarium that will break the ice at your neighborhood parties, then why not attempt to acquire a Rhinopias!
These are good times to be a marine aquarist! I know the economy is in a bit of a slump and we are in a long and important war against terrorism. But even so, there are some good things happening in the marine aquarium trade. One of the most exciting things is that unusual fishes are showing up in the trade greater regularity! For example, there are dottybacks, damsels and wrasses that I have seen in aquarium stores for the first time in the last year. Many of these are being collected in places where collecting did not occur in the past (this is especially true for Indonesia). Members of the genus Rhinopiashave also been showing up in the aquarium trade with greater regularity. These amazing scorpionfishes are the subject of this article.
The members of the genus Rhinopias have long been considered the “Holy Grail” of aquarists who keep rare and unusual fishes. The genus Rhinopias contains six species (some suggest one of these is not valid) and none of these are considered to be common. But their apparent rareness may be due in part to their cryptic behavior, excellent camouflage and the fact some species live in habitats that are not readily explored. The species that comprise the genus are: the lacey or Merlet's scorpionfish ( Rhinopias aphanes ), the Easter Island scorpionfish (Rhinopias cea ), the Japanese scorpionfish ( Rhinopias argoliba ), Eschmeyer's scorpionfish ( Rhinopias eschmeyeri ), the weedy scorpionfish ( Rhinopias frondosa ) and the strange-eyed scorpionfish ( Rhinopias xenops ). All of the Rhinopias have deep, laterally compressed bodies, eyes set high on top of their heads and most species have dermal appendages above their eyes, on the jaws and the body surface (the number various between the species and even from one individual to the next).
The Species In The Trade :
There are two species that regularly show-up in the aquarium trade: The weedy scorpionfish ( Rhinopias frondosa ) and Eschmeyer’s scorpionfish ( R. eschmeyeri ). The weedy scorpionfish is a wide-ranging species that occurs from East Africa to the Caroline Islands, north to Japan and south to Mauritius. Apparently, most of those being collected for the aquarium trade are coming from Sri Lanka. This scorpaenid attains a maximum length of 9 inches. It has been reported at depths from 10 to 297 on bottoms sandy, macroalgae, rubble and rocky substrates (Eschmeyer et al. 1973, Myers 1989).
Eschmeyer's scorpionfish has been reported from Mauritius to Sri Lanka (Lieske and Myers 1994), although I have seen specimens from the Philippines and Papua New Guinea and have observed it in Indonesia. This species is usually uniform in color and can be lilac, yellow, orange or brick red and attains a maximum length of 7.5 inches. Rhinopias eschmeyeri is reported to occur on open sand bottoms at depths from 7 to 132 feet (Conde 1977, Debelius 1993).
I should point out that at least one fish expert (Rudie Kuiter) has suggested that R. eschmeyeri is not a valid species, but a variant of R. frondosa. One characteristic used to tell the two species apart is the membrane between the spines and rays of the first and second dorsal fins. In R. eschmeyeri the membrane is incised - that is, the edge of the dorsal fins are nearly straight. In some individuals of the Eschmeyer’s scorpionfish, the first dorsal fin is almost sail-like. In the weedy scorpionfish the membrane is deeply incised so the dorsal edge appears to be jagged.
Rhinopias eschmeyeri also exhibits a uniform body color, while R. frondosa usually has round and oblong pale spots and blotches (these can be less conspicuous in some individuals). In R. eschmeyeri the supraorbital appendages are unbranched and flattened (they are leaf-like), while those of R. frondosa are branched. It may be these differences represent sexual dimorphism within R. frondosa. I have seen photos of apparent pairs ofRhinopias, where one fish was a “perfect” R. eschmeyeri and the other fish looked more like R. frondosa. The verdict is still out, with more study being required to determine how many Rhinopias spp. actually exist.
The scorpionfishes in the genus Rhinopias are highly sought after by the collector of the rare and unusual. This is Rhinopias aphanes, the lacey scorpionfish, which is thought to mimic a crinoid.
The weedy scorpionfish is the most commonly seen species in the aquarium trade. This species often sports rings or spots on the body, but in some individuals, like the one pictured here, they can be indistinct.
The first dorsal fin of Eschmeyer’s scorpionfish is sail-like, with no or very reduced incisions between the dorsal spines.
The Rhinopias spp. are known to shed their cuticle, or the outer epidermal layer. This helps rid the body of algae, parasites or encrusting organisms. In some individuals shedding can occur quite often. For example, a R. eschmeyeri was reported to shed about every 12 days (Eschmeyer et al. 1973). The frequency of shedding may increase if the fish is suffering from parasitic infections. Do not freak out if the eyes of your Rhinopias become cloudy – they sometimes do before the fish shed. These scorpionfish may also position themselves in front of strong water flow to facilitate the shedding process.
These fish rarely swim, but move about by crutching along the bottom on their pectoral and pelvic fins. When hunting they remain motionless and wait for their prey to approach within striking distance or they slowly stalk their quarry. When a specimen is very hungry and use to food presentation in the aquarium, it may "hop" rapidly toward a prey item, rather than approaching it slowly. When they get close enough to their prey the Rhinopiaswill_ lunge forward and suck in its victim. Rhinopias_ will also rock forward and backward in order to mimic a piece of debris sitting on the bottom.
Keeping them In Captivity
All the Rhinopias readily adapt to captivity and because of they are relatively inactive they can be kept in smaller aquaria (Dinesen and Nash 1982, Howe et al. 1988, personal observation). I would suggest that a smallerRhinopias be housed in an aquarium of at least 20 gallons, while larger adults will do fine in a standard 30 gallon tank. Although some décor is needed to help your Rhinopias “feel at home,” do not over do it. These fishes (especially R. eschmeyeri ) often sit in repose on open sand, mud or rubble bottoms. Because these fishes tend to spend most of their time in the open (unlike some scorpionfishes, which are more cryptic) they make an interesting addition to the reef aquarium.
Live food (e.g., ghost shrimp, mollies, guppies) will be needed to initiate feeding and many individuals may never accept anything but live fare. You should attempt to train your Rhinopias to take pieces of shrimp, squid and fish off of a feeding stick. One thing you should avoid is feeding your scorpionfish a diet consisting only of feeder goldfish. Raw goldfish flesh contains thiaminase, an enzyme that causes the breakdown of thiamin. If you feed your scorpionfish a diet that consists only of goldfish, they may become thiamin deficient, which can result in feeding cessation, clamped fins and nervous in coordination. If you have to feed them live food, gut pack mollies, guppies and/or ghost shrimp with a nutritious food (e.g., Cyclop-eeze®) before you feed them to your Rhinopias(some individual may be reluctant to feed on live ghost shrimp).
Behavior
Hepatic lipidosis, or fatty degeneration of the liver, has been reported in a scorpionfish fed only fresh hake. This condition can cause liver failure, which leads to suppression of the immune system, hemorrhaging and anemia. Lipidosis is best avoided by giving your scorpionfish as varied a diet as possible and by not overfeeding. I would recommend you feed your scorpionfish to satiation twice a week.
They can be housed with other fish, but I would avoid keeping them with species that eat encrusting invertebrates because they mistake the Rhinopias as a rock covered with food! Although on some occasions these fish may not harm your Rhinopias, in my mind it is not worth the risk. You should also be careful when putting them in tanks with other predatory fish. Although the deep body and venomous spines of these fish may dissuade most predators, smaller specimens may be eaten by larger frogfishes, other scorpionfishes or large groupers. An Eschmeyer's scorpionfish I was keeping met a tragic end when its head was engulfed by a smaller striated frogfish ( Antennarius striatus ). I had placed several feeder fish in the tank and was watching these two fish stalk them. The Rhinopias was moving around a piece of coral when the frogfish decided to try and eat it! I quickly grabbed the frogfish by the tail and it released the Rhinopias, but the eye of the scorpionfish was damaged, became infected and it died several days later. I personally think that these fishes are best kept in a species tank – that is, an aquarium by themselves. It is not worth the risk of having you Rhinopias harmed by a tankmate.
These fishes are highly predatory and will eat any fish that they can ingest. Don’t underestimate the size of a Rhinopias mouth! If you see a Rhinopias yawn you will realize that they can eat relatively large prey items. I had an Eschmeyer’s scorpionfish eat an anemonefish that I thought was to deep-bodied for it to ingest – boy, was I wrong! That said, my good friend Mitch Carl tells me that his 5-inch Rhinopias frondosa will not eat a fish larger than a molly. The Rhinopias will also consume ornamental crustaceans, including shrimps and crabs.
Almost all the Rhinopias I have kept or seen in captivity had abraded lower jaws. They apparently swim against the plastic bag during shipping, which results in injury to the skin on the lower jaw. In most cases, this wound gradually heals, but it is a possible portal for bacterial infection which can lead to death of the fish. I have seenRhinopias die as a result of severe bacterial infections that manifested themselves as skin lesions on the body. These fishes can also suffer and succumb to ich ( Cryptocaryon irritans ) and coral fish disease ( Amyloodiniumocellatum ). It is possible to treat them with common anti-parasitic medications (be careful when using copper-based meds) or by dropping the specific gravity (down to 1.012-1.014 for a couple of weeks).
Of course, these piscine jewels command big bucks! But if you are really in to the odd and want to display a fish in your aquarium that will break the ice at your neighborhood parties, then why not attempt to acquire aRhinopias!
This is the classic form of the weedy scorpionfish, with conspicuous markings and long dermal appendages. This individuals is now on exhibit at the Omaha Henry Doorly Zoo.
The lacey scorpionfish shows-up in the aquarium trade on rare occasions. It always has numerous skin flaps on the head, body and fins, antler-like growths over the eyes and dark lines on the body.
This beautiful weedy scorpionfish, photographed by Eric Reynolds of Aquamarines, was collected in Sri Lanka.
Acknowledgements :
I want to thank Dennis and Eric Reynolds (Aqua Marines), Randy Walker (The Marine Center), Jim Walters (Old Town Aquarium, Chicago) and Julian Sprung for helping me acquire Rhinopias over the years. Mitch Carl (Omaha Henry Doorly Zoo) and Jim Walters shared some of their observations on Rhinopias frondosa (if your in the Omaha area, you should go see the beauty at the Henry Doorly Zoo!). Thanks to Eric Reynolds for supplying the photo of the orange R. frondosa.
References
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Conde, P. B. 1977. Nouvelles observations sur les scorpaenides du genre Rhinopias a Maruice. Rev. fr. Aquariol. 4:19-20.
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Debelius, H. 1993. Indian Ocean tropical fish guide. Aquaprint Verlags, Neu Isenburg. 319 Pp.
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Dinesen, Z. D. and W. J. Nash. 1982. The scorpionfish, Rhinopias aphanes Eschmeyer from Australia. Jap. J. Ich. 29:179-184.
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Eschmeyer, W. N., Y. Hirosaki and T. Abe. 1973. Two new species of the scorpionfish genus Rhinopias, with comments on related genera and species. Proc. Calif. Acad. Sci. 40:285-310.
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Howe, J, G. Crow and J. Herbert. 1988. The strange-eyed scorpionfish, Rhinopias xenops. Freshwater and Marine Aquarium, 11:8-11.
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Lieske, E and R. Myers. 1994. Collins Pocket Guide. Coral reef fishes: Indo- Pacific and Caribbean. HarperCollins Publ., London, 400 Pp.
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Myers, R. F. 1989. Micronesian Reef Fishes. Coral Graphics, Guam, Pp. 228.