TWINSPOT LIONFISH (DENDROCHIRUS BIOCELLATUS)

A twinspot lionfish slowly moves around a coral colony as it hunts for food at night. The large pectoral fins block the prey's view of the caudal fin, enabling the lionfish to propel itself forward in a more stealthy fashion. © Scott W. Michael

I have long been a fan of lionfishes. In fact, these fishes were partially responsible for baptism into the marine aquarium hobby over 30 years ago. I have been fortunate enough to keep all the species available in the trade. Of these, my favorite is still Dendrochirus biocellatus. This member of the subfamily, which is referred to commonly as the twinspot, ocellated or Fu Manchu lionfish, is a unique species that is less frequently seen in aquarium stores than many of its kin. The two barbels on the upper jaw and pair of ocelli on the soft dorsal fin set D. biocellatus apart from all of its relatives. In this article, I would like to share some of my musings, and the observations of others, on this unusual scorpaenid.

Lionfishes are members of the family Scorpaenidae (scorpionfishes) and the subfamily Pteroinae. There are six genera in this subfamily and approximately 22 species. The two genera that you most often see in the aquarium trade belong to the genera Dendrochirus and Pterois. Members of these two genera are easily separated by the form of their pectoral fins. In Dendrochirus spp. the pectoral fin rays do not reach the base of the caudal fin, they are branched and are connected by a membrane over much of their length.

The twinspot lionfish slinks along the bottom and is rarely seen in the open during the day. This individual was photographed in Milne Bay, Papua New Guinea. © Scott W. Michael

The twinspot lionfish is known from Mauritius to the Society Islands, north to Japan and south to Australia. It has been reported at depths of 1 to 40 m (3.3 to 132 ft.) in lagoons, on coastal fringing reefs and on patch reefs. It is also found on outer reef faces and slopes. It tends to prefer microhabitats with rich stony and/or soft coral growth. It is a secretive species that spends the daytime hours hanging upside down in deeper crevices and caves. A diver might occasionally catch a glimpse of one of these fish moving from one crevice to another during the day. However, it is most readily observed during night dives, at which time it comes out to hunt.

The long filaments on the upper jaw of this fish are responsible for one of its common names - Fu Manchu lionfish. They may serve to obliterate the head shape so it is more difficult for a prey species to recognize the lionfish as a threat or may even serve a luring function. © Scott W. Michael

Dendrochirus biocellatus is thought to feed mostly on crustaceans, although food habit data is lacking for this species. It exhibits an unusual behavior when it feeds. It will snap its dorsal spines and shake its head from side-to-side as it approaches its prey. This behavior may serve to distract, or possibly attract, the prey item. Thaler (2004) has suggested that the fleshy barbels that extend from the upper jaw may act to attract fish into striking distance. It often stalks its quarry by slinking along the bottom or around reef structure like a cat, and moves forward, either by "hopping" on its pelvic fins or by undulating its caudal fin. When it is about one-half a body length away from its prey, it lunges forward with amazing speed to ingest it.

The color of the ocelli on the soft portion of the dorsal fin can lighten and may indicate an individuals social status or state of excitability. © Scott W. Michael

The ocelli on the soft portion of the dorsal fin may serve a communicative function. They can change from black to a faded gray. This color change often occurs during aggressive interactions and courtship. In agonistic interactions the ocelli will typically fade in the dominant individual, while during courtship the spots fade in males. Thaler (2004) reports that the ocelli can take on a turquoise color and that the eyespot adopts this color when the fish is excited (whether by food, a mate or a competitor).

Aquarium Husbandry

The twinspot lionfish is considered to be the most difficult member of the subfamily to maintain. This is due to the fact that they can be reluctant to eat anything but live food. The best diet you can provide for D. biocellatus are ghost shrimp. You should gut pack these (feed them a nutritious flake or frozen food) before you feed them to you twinspot lionfish. I have yet to have an individual that would not eat these crustaceans. However, I have not had much success getting D. biocellatus to accept nonliving foods, including bits of food on the end of a feeding stick. So before you purchase a D. biocellatus, make sure you have access to ghost shrimp. Juvenile twinspot lionfish will also eat live brine shrimp. You should feed your twinspot lionfish several of these shrimp every other day.

A twinspot lionfish secreted in its daytime dwelling place - in a coral cave on a Philippine reef. This animal is diurnally illusive and will need some good hiding places in the home aquarium. Compare the color of this individual with those in the other photographs included - note the darker ocelli. © Scott W. Michael

Feeding a twinspot lionfish in an aquarium that contains other aggressive feeders can be a problem. Therefore, potential competitors, like groupers, soapfishes, snappers and triggerfishes do not make good D. biocellatus tankmates. This lionfish may have difficulty getting anything to eat with these more aggressive gluttons. You may have to present ghost shrimp to the twinspot lionfish in a fine meshed fish net. Place the shrimp in the net and move it slowly toward the area where the lionfish is hiding. With time, this lionfish can usually be trained to swim to the net opening and snap up the shrimp inside. This method is also effective for feeding this fish in a reef aquarium. Large angelfishes, triggerfishes, pufferfishes and porcupinefishes can also cause problems when kept with D. biocellatus. They have been known to nip the fins of this fish.

This lionfish will do better in a smaller tank where they are kept on their own than in a larger community tank where feeding them can be difficult. Adult twinspot lionfish can be kept in tanks as small as 20 gallons. It is imperative to provide this secretive fish with caves, crevices and overhangs in order for it to properly acclimate. I have had even had specimens hang upside down under the heads of large leather corals.

Adult twinspot lionfish will eat smaller members of their own species and larger specimens (presumably males) will behave aggressively toward conspecifics. When displaying the fan-like pectoral fins are extended forward, the dorsal spines are erected and the body quivers. Smaller individuals will usually flee when a larger individual display, but threats may escalate into fighting if both fish are similar in size and one specimen does not back down. In this case biting and dorsal fin jabbing may occur, which can result in torn fins, scale loss, damaged eyes and even death if the fish are not separated. If you keep more than one twinspot lionfish in a larger aquarium (e.g., 70 gallons or more) they will usually avoid each other, but in smaller aquaria dominant specimens often stalk and injure subordinate conspecifics.

The twinspot lionfish is a wonderful addition to the smaller reef aquarium. They will not harm sessile invertebrates, but will eat crustaceans and some smaller (especially benthic) fishes. © Scott W. Michael

It is not uncommon for lionfish lovers to want to keep more than one member of this subfamily in the same tank. It is possible that other Dendrochirus spp. will fight with D. biocellatus. This is especially true if both individuals are male or if one congener is placed in the aquarium after the other. Although these encounters are usually limited to lateral displays, gill cover flaring and head shaking, if one individual does not back down they may bite each other. I have seen the shortfin lionfish (Dendrochirus brachypterus) grasp the head of an opponent in its mouth and vigorously shake it from side to side. This behavior can result in damage to the jaws of the fish that is attacked. Individuals may also bite the flanks of congeners or ram each other with their venomous dorsal spines. Although a lionfish stung by another will usually not die as a result, it can cause temporary distress, including an increased respiration rate (as much as 3 times its normal rate) and decreased swimming activity. If one

lionfsh is persistently attacked by another they should be separated or the subordinate individual may cease feeding and end up dead. Another thing to be aware of when keeping more than one lionfish in the same aquarium is that larger lionfish have been known to prey on smaller individuals.

Like all the lionfishes, D. biocellatus is suitable for a reef tank if you are not interested in keeping shrimp and smaller fishes, especially benthic species like gobies and blennies. This lionfish is less of threat to more active fish species than its relatives due to its slightly smaller mouth and unique hunting behavior. Do not expect to see your twinspot lionfish much if your aquarium is replete with live rock. Smaller specimens tend to be more secretive than adults are and some larger individuals will come out into the open as they become more accustomed to aquarium life. The best way to view these fish in a reef aquarium is to place a red fluorescent or incandescent bulb over the tank at night.

The dorsal spines of this species are not only venomous, but are also snapped from side to side as this fish hunts, possibly functioning to lure prey within striking range or to distract their quarry as the twinspot slinks forward into striking range. © Scott W. Michael

All the lionfishes are venomous. An injection of venom from the fin spines can cause intense pain and swelling. For this reason, it is important to be very careful when ever you place your hands in your aquarium. Make sure you know where your lionfish is before moving aquarium décor or equipment. If you are stung by your twinspot lionfish, immediately immerse the wound in hot, nonscalding water (from 43.3 to 45 ºC, or 110 to 113 ºF, for 30 or 40 minutes or until pain has diminished) or heat it with a hair dryer. The heat will denature the protein that constitutes the venom and prevent it from spreading through your body.

Although the twinspot lionfish is more demanding than some of its relatives, this fish can make a fascinating addition to the species tank or reef aquarium.

References

Michael, S. W. 1998. Reef Fishes. Volume 1. Microcosm, Shelburne, VT. 624 pp.

Thaler, E. 2004. Lionfishes - Personal Observations on their Behaviors and Suggestions for Aquarium Care. Coral 1(4):36-40.

BEHOLD THE DRAGON!

An exquisite example of a dragon moray from one of the Izu Islands of Japan. Note the brillant orange coloration that some in the ornamental fish trade have suggested is only found on those specimens from Japan - this is not the case.

In my mind, the dragon moray (Enchelycore pardalis) is the most beautiful and fearsome-looking of all the muraenids. With its crooked jaws, its always visible, needle-sharp teeth, the "horn" over each eye, and the tubular nostrils, it is truly as frightening to look at as its mythical namesake! It is also one of the most colorful of all the morays. The body and head can be chocolate to light brown, with varying degrees of orange. (The truly amazing individuals have bright orange on the anterior portion of the body and head.) There are white spots and bands on the body, head and jaws. The white mouth is tattooed with a series of dark lines.

It has been suggested that those dragon morays from Japan are the most beautiful of all. But the coloration of individuals varies greatly within populations. Some have suggested that these chromatic differences may represent sexual dichromatism, but this has never been proven by eternal examination or observation of spawning behavior. Therefore, at this time it is just a hypothesis.

The threatening posture of a young dragon moray from Japan (note the color variation in the photos, all of which were taken on Japanese rocky reefs).

Observing Dragons in the Field

On a trip to Osezaki, Japan in 2003, I observed one of these morays among the small boulders that comprised a rocky jetty. I was upset because I was out of film and worried that I may not see another one during my three week stay in Japan. Boy was my worrying unnecessary! I would end up seeing over 50 dragon morays at the two areas we visited. On one dive, where I actually went looking for these morays, I saw nine individuals in about 50 minutes! I found that at Osezaki, it is most common on the outer bay side of the Osezaki Peninsula. I typically found it in interstices between the large coralline-encrusted boulders that made up a boulder tract that runs parallel to the coastline. (I rarely saw them among the rocks that were covered with macroalgae.) Individuals were also seen partially hidden between smaller rocks, in crevices under limestone overhangs, and in large fissures in large rocky pinnacles and outcroppings. I observed it at depths of 1.5 to 27 m (5 to 88 ft.).

The dragon moray is often seen sharing its rocky lair with Stenopus shrimp, which may clean them on occasion.

The dragon moray tends to be quite shy. Individuals are usually seen with only their heads protruding from a crevice (occasionally the front portion of the body may also be in view) and many will quickly pull into their refuge if closely approached. Although I never observed more than one dragon moray in the same crevice, they were often not far from one another. At one site, I saw five individuals in an area of about 3 x 9.2 m (20 x 30 ft). Occasionally, they were also observed in close proximity to the Kidako moray (Gymnothorax kidako). On several occasions I saw individuals being serviced by cleaner wrasses and banded coral shrimp (Stenopus hispidus). On two occasions I saw the banded coral shrimp cleaning the jaws and mouth of a dragon moray.

Keeping Dragons

This moray's contrasting combination of a menacing appearance and colorful attire makes it a great display animal for the larger home aquarium. But unfortunately, the dragon moray is not readily available in the aquarium trade and when it is available it commands big dollars. It is a fish-eater that will ingest anything that can fit into its expandable jaws. Although an uncommon event, larger specimens have even been known to bite and mutilate fish that are to large to swallow whole.

The orange headed color form is coveted by marine aquarists but is rarely available in the US aquarium trade. This adult specimen was photographed off the Izu Islands.

The dragon moray is very cryptic, especially smaller specimens, and must be provided with suitable shelter sites to facilitate acclimation. With time, it will become less of a recluse, spending more of the daylight hours with at least its head protruding from a hole or crevice. Some specimens will even begin to lay out in full view and become quite tame. The dragon moray will eat live feeder fish in captivity, although it may take several weeks, or even months, before some larger specimens commence feeding.

With time most dragon morays can, and should, be switched to long strips of fish flesh (e.g., smelt, orange roughly, haddock) and squid. Most morays can be enticed to eat non-living food by impaling it on the end of a feeding stick (I use a piece of rigid airline tubing with a sharpened end) and moving it in front of their head. It is also important not to feed your moray too frequently, because over feeding can lead to fatty infiltration of the liver, which impairs the functioning of this organ. It is not uncommon to see animals that have excessive fat deposits on the head and body in public aquariums, probably as a result of being overfed. Field studies suggest that morays eat infrequently, therefore in order to prevent this condition I would recommend feeding your eel to satiation twice a week. Also an overfed moray may regurgitate its partially digested meal, which can make a mess of your tank. Morays usually ingest one larger meal every three or four days.

A large, aging dragon eel with cloudy eyes and more elongate jaws. This one is shown in prime dragon habitat - among immense, coralline encrusted boulders along with some hinge-beaked shrimp.

It is not uncommon for morays to refuse to eat on occasion. This may occur if the eel is being overfed, if the water quality in the tank has deteriorated, the water temperature drops significantly, or sometimes occurs for no reason at all. The problem can often be rectified by performing a partial water change, offering your eel different types of food and by being patient. Continue to offer the eel food, even if he has shown no interest during recent attempts. Just keep trying. Keep trying different types of food to see if one certain food triggers a feeding response. I have found that a fasting moray will often have a hard time resisting cephalopods (e.g., squid, octopus) if they have been on a fish-only diet. Other foods I have used to initiate a feeding response in a finicky moray include smelt, orange roughly, and haddock.

This Japanese example of the dragon moray exhibits a more muted coloration (a color form often seen in the aquarium trade).

Because their large teeth can inflict serious injury to conspecifics, and fighting is likely to result, I would not risk placing two specimens in the same tank, unless they are a mated pair and you have an extra-large aquarium (e.g., 180 or more). You can keep juveniles of this species with other morays, but adults may attack other eels housed with them, especially if other morays are introduced after the dragon moray. If you are going to keep other eels with an adult dragon moray, they should be placed in an X-large tank with numerous hiding places. The dragon moray should be introduced to the tank last, and all the eels should be of similar size or the dragon moray should be slightly smaller.

An adult dragon moray can make a spectacular display animal in the home aquarium, however, be aware that it is a threat to many potential fish tankmates and is known to go on the occasional hunger strike.

The threat display of the dragon moray is spectacular. It will open its jaws as wide as possible, laterally flatten the gill region, cock its head to one side and erect its dorsal fin. I have seen other morays that were nearly as long as the dragon moray and well established in the tank before the dragon moray was added, flee to the upper corner of the tank when threatened by one of these menacing-looking beasts.

© Scott W. Michael

PICTICHROMIS DINAR: A NEW SPECIES

Dr. John Randall and Karen Schultz have made it official - Pictichromis dinar is a new species from Western Sulawesi. While it looks very similar to a couple of other dottybacks in this genus (see this post for more information and photos), they have concluded, through the use of DNA analysis, that it is indeed distinct. But can you tell the difference from external characteristics alone? Good question. Apparently, the new species (seen above),

Here is the actual abstract from the paper on the fish:

"A new pseudochromid fish species, Pictichromis dinar, is described from five specimens from the western side of the Gulf of Tomini, Sulawesi, Indonesia, where it occurred on a drop-off in 15 to 25 m. It is bright purple anteriorly and abruptly bright yellow posteriorly in life, hence remarkably similar to P. paccagnellae (range from Bali and Sulawesi to Vanuatu), and to P. coralensis (range from Queensland to New Caledonia). The demarcation of purple and yellow is generally more anterior and more slanting in P. dinar. The caudal fin of P. paccagnellae and P. coralensis varies from slightly rounded to slightly emarginate, compared to distinctly emarginate in P. dinar, the caudal concavity is 9.9-11.2% SL. Also, P. dinar has modally one more gill raker. Thirty specimens of Pictichromis dinar and 28 of Pictichromis paccagnellae were assessed at 628 base pairs of the mitochondrial cytochrome c oxidase I gene. No haplotypes are shared between the species, and within species sequence divergence (d = 0.003) is an order of magnitude lower than sequence divergence between the two species d = 0.06). This is consistent with reproductive isolation and species-level designation. "

Randall, J. E. and J. K. Schultz. 2009. Pictichromis dinar, a new dottyback (Perciformes: Pseudochromidae) from Indonesia. Aqua, Int. J. of Ichthyol. 15 (4):169-176

UNDESCRIBED SEA BASS FROM EASTERN ATLANTIC

Undescribed Serranus sp. from Western Africa.

The Central and Eastern Atlantic is home to a number of reef fish species, some of which are very similar to more familiar fishes found in the Western Atlantic. For example, you have the Marcella butterflyfish (Prognathodes marcellae), which is similar to the bank (P. aya) and threeband butterflyfish (P. guyanensis) of the Western Atlantic. Then there is the ever-popular resplendent angelfish (Centropyge resplendens), known from Ascension Island (in the Central Atlantic), which is similar to its Western Atlantic counterpart, the cherubfish (C. argi) and flameback pygmy angelfish (C. aurantonotus) (Note: Wirtz et al. have recently collected a specimen of the later species from the Gulf of Guinea). The lesser known West African coral hind (Cephalopholis taeniops), which is very similar to its Western cousin, the coney (C. fulvus) and the African Creole wrasse (Clepticus africanus) that is a sister species of the Creole wrasse (C. parrae).

An example of this same fish in the aquarium. The banded color pattern is displayed when the fish is stressed/frightened.

Recently, a lovely little serranid has been imported from Western Africa. It is a handsome little fish that, thanks to the efforts of Joe Russo, has become quite readily available. According to Joe, they are collected in fairly deep water (greater than 35 m). Dr. Peter Wirtz, an expert on the fish communities of this region, tells me that he has seen this fish at depths of 50 cm (these were juveniles) to at least 30 m. He also reports that it is a solitary species. Wirtz et al. (2007) report that this fish is common on hard and soft bottoms at São Tomé and Príncipe (Gulf of Guinea). It is somewhat variable in color, as you can see in the two photos included with this post.

At first blush, it exhibits anatomical similarities to some of the wonderful aquarium serranids from the tropical Western Atlantic. One of my favorites is the semi-social chalk bass (Serranus tortugarum). While related, the Serranus sp. from Africa differs greatly from the chalk bass in disposition. The undescribed Eastern Atlantic serranid is a true hellion! It is both aggressive and highly predatory (it appears to relish any fish or crustacean small enough to swallow whole). So, while you may be tempted to plop one of these beauties into your moderately-peaceful community aquarium, you may want to think again! Sanjay Joshi has one in a huge tank (500 gallons) and it has caused him much consternation attacking and eating its tankmates. While a maximum length has yet to be established, it can get at least 7 cm in total length.

There are other lovely fish from this region that Joe is bringing in to the US market. I hope to feature some more of these in upcoming posts.

References

Wirtz, P., C. Eduardo, L. Ferreira, S. R. Floeter, R. Fricke, J. L. Gasparini, T. Iwamoto, L. Rocha, C. L. S. Sampaio and U.K. Schliewen. 2007. Coastal Fishes of São Tomé and Príncipe islands, Gulf of Guinea (Eastern Atlantic Ocean)—an update. Zootaxa 1523: 1–48.

© Scott W. Michael

COLOR FORMS OF NEMATELEOTRIS HELFRICHI – IS THERE MORE THAN ONE SPECIES HERE?

The best known color form of Nemateleotris helfrichi from Micronesia.

Micronesian color form of N. helfrichi. Compare with Cook Island color form below.

There are probably a lot of you out there that encountered their first Nemateleotris helfrichi within the pages of Helmut Debelius’ FISHES FOR THE INVERTEBRATE AQUARIUM? I received a copy of this book in the mid-1980’s and was blown away by Helfrich’s dart or firefish! While the fish was new to me, it certainly was not new to science, having been described by Dr. Jack Randall and Dr. Gerald Allen all the way back in 1973.

This lovely fish is known to occur around the Ryuku and Ogasawara Islands, in Micronesia and Polynesia (the type locality being Tahiti). This fish started making its way into aquarium stores (to the best of my recollection) in around 1991 or 1992. The first specimens I was able to buy were from Micronesia. They had the characteristic coloration of the fish pictured in Debelius’ book. This same color form appears in John Randall’s FISHES OF THE SOUTH PACIFIC. He describes the coloration of the fish as follows:

“..lavender, gradually shading posteriorly nearly to white and anteriorly on head to bright yellow; top of head from interorbital to origin of first dorsal fin with a narrowing band of bright magenta, merging with violet on dorso-anterior quadrant of iris; elevated anterior part of first dorsal fin orange and back with a broad, pale blue leading edge; rays of second dorsal and anal fins tipped with yellow or orange caudal fin pale yellow.”

Cook Island color form of N. helfrichi - compare the head coloration with that of the two specimens from Micronesia above.

A head shot of the same specimen from the Cook Islands.

This certainly describes the populations of N. helfrichi from Micronesia and Japan "to a T." But it turns out that the population of N. helfrichi from Polynesia is quite different chromatically. I had seen photos of N. helfrichi from this region before and knew the color differed. But recently my good friend Kevin Kohen was able to acquire some live specimens from the Cook Islands. While very expensive, I wanted to see this “color form” of N. helfrichi first hand and take photos of it.

As you can see from the photos above, the Cook Island fish differs rather dramatically from its Japanese/Micronesian cousin. Note for example the differences in the color of the head, the metallic blue on the “face,” the black line over the upper jaw and the subtle differences in coloration of the anal fin.

The holotype for the species N. helfrichi is a specimen from Tahiti (Randall and Allen 1973). Not surprisingly, the holotype is the same color as the Cook Island fish. That would suggest that the Polynesian fish are actually N. helfrichi, while the Micronesian/Japanese populations MAY represent an undescribed species. DNA analysis will be needed to emphatically answer this question. More to come on this one in the future.

© Scott W. Michael

COLLETTE’S REEF BASSLET

A specimen of Liopropoma collettei from the Philippines (at least that is where I think it was collected!).

Holotype of Liopropoma collettei from the Hawaiian Islands.

In past posts we have been looking at some of the different reef basslets (genus Liopropoma). In one of my last posts on the genus a comment was made about L. collettei and how it was more attractive than L. susumi – well what do you think? The specimen above is an individual I recently acquired from Kevin Kohen (ww.liveaquaria.com). Liopropoma collettei is known from Papua New Guinea, the Philippines and the Hawaiian Islands. It has been collected on coral reef at depths of 6 to 34 m among stony corals, like Porites compressa and P. lobata. This species attains a maximum length of 8 cm (individuals from Hawaii are larger than those from other locations).

Randall and Taylor (1988) reported in their revision of the genus that Hawaiian specimens of what they call L. collettei differs from those from the Western Pacific in having 15 or 16 instead of 14 or 15 pectoral rays, no enlarged pore anterior to the posterior nostrils and in the total length (as mentioned above the Hawaiian specimens are larger). They decided to lump the two populations together as the same species based on similarities in body proportions and "especially in color pattern.." But, these researchers had never seen a live specimen from the Western Pacific. While the members of the two populations are similar in overall color, there are some subtle differences, as you can see in the photos included above. For example, in Hawaiian specimens the stripes on the body are dark brown (those on the fish from the Philippines are obviously reddish brown). While the Western Pacific population may not represent a distinct species, it certainly might (DNA analysis will be one way to determine if this is the case.)

I have been keeping one other specimen of L. colletti and have found it to be quite cryptic. In my experiences, the Liopropoma are all secretive, but some (e.g., L. swalesi) are more reclusive than others (e.g., L. carmabi is not as shy). I would say that L. collettei is a more reclusive species, maybe not quite as bad as L. swalesi, but close. My first specimen is in a nano-reef and is rarely seen. The only time I observe it is when it moves from one interstice to another or I occasionally see it peering out from under a ledge when only the actinics are on. If you invest in one of these beauties, do not expect it to parade back and forth along the front of the tank. That is why I recommend the members of this genus for nano-reef aquariums - if you contain them in a smaller area, you will be able to observe them with greater ease.

References:

Randall, J. E. and L. Taylor. 1988. Review of the Indo-Pacific fishes of the Serranid genus Liopropoma with descriptions of seven new species. Indo-Pacific Fishes 16, 47 pp.

© Scott W. Michael