Lions and triggers and eels…oh my! Nothing embodies both the beauty and danger of the oceans more than lionfish. Not only are they astonishingly beautiful with their gracefully flowing fins, dramatic colorations, cautious movements, and fish-gulping mouths, but they're equipped with venomous spines capable of delivering painful stings upon an unwary hobbyist. In spite of all this bravado, lionfish are peaceful, extremely hardy and disease-resistant tank inhabitants that are well suited for the intermediate saltwater hobbyist.

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Two beautiful lionfish in flight. This photo displays the pectoral fins of both the P. radiata (left) and P. antennata (right). Both fish are approximately 8 months old and 7-8" long. Photo by Frank Marini.

A Lionfish for Any Tank?

The very popular Volitans lionfish is considered the ultimate lionfish by most marine aquarists, and other members of this genus, such as the Antennata and Radiata, lionfish are frequently found at local fish stores. As adult fish, they are considered medium sized (10-15" long with tail) and, while they are relatively inactive swimmers, they still must be housed in a fairly large aquarium (75 gallons or more). So, does this mean that people with smaller tanks can't enjoy lionfish? Certainly not. Another type of lionfish, the "dwarf lions," fills this niche and is commonly available. Dwarf fuzzy lions, dwarf lions, and Fu Man Chu lions stay reasonably small (under 8" long including tail) and do very well in tanks in the 30-50 gallon range. These smaller lions are every bit as beautiful as their larger cousins, may also pack a powerful sting, and ingest proportionally sized foods (Burgess, 1991). Let me start out by mentioning that common names for lionfish vary from place to place, and one person's "turkeyfish" is someone else's Russell's lion. I see this incorrect identification of lionfish weekly at local fish stores; almost every tank of lionfish for sale contains misidentified species, and they are all lumped into two groups: large lionfish are all called Volitans lions, and any small lionfish are identified as "dwarf lionfish" (Michaels, 1999). While I frequently use common names to describe certain species of lionfish, it is preferable that we identify these fish by species names. In this way, both interested parties understand which fish are being discussed [Figure 1].

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Figure 1. An imposing view, face-to-face with a 12" long P. volitans lionfish. This lionfish will reach a maximum size of 15" within eighteen months. A fish this size requires an appropiately sized large tank. Photo by Frank Marini.

Classification and Distribution

Lionfish are members of the scorpionfish family (Scorpaenidae) and, in particular, the subfamily Pteroinae. There are 5 genera and approximately 16 individual species in the taxon, with two of these genera and 11 of the species common in the saltwater hobby (Eschmeyer, 1986). The two genera available to hobbyists are Pterois and Dendrochirus; these fish are easily identified by both the adult size of the fish and the shape of their beautiful pectoral fins. In Dendriochirus lionfish, the pectoral rays do not reach the base of the caudal peduncle, and, in general, the fin rays are branched and form a solid fan shape by a connecting membrane that spans each fin ray. Pterois lionfish have elongated fins reaching well past the tail, with many fin rays individually sheathed in a long flowing membrane.

Lionfish are found in the Indo-Pacific (central and western Pacific oceans) and the Red Sea. A few of the lionfish have a wide distribution, such as the Russell's lionfish (Pteriois russelli), which are found on both reef and rocky environments in subtropical and tropical waters, while other lions have extremely limited ranges, such as the Hawaiian lionfish (Pterois sphex), which are found only in waters surrounding the Hawaiian Islands.

Captive Care of Lionfish

The size of the aquarium needed to house one or more lionfish will depend on the species of lionfish chosen. Members of the smaller dwarf lionfish can be kept in smaller tanks. Because these fish are sedentary and tend to hide in the rockwork or upside down in caves, smaller tanks (between 30-55 gallons) are suitable [Figure 2]. In general, members of the Pterois family (the mid-to-large bodied lions) require larger tanks in the range of 50-100+ gallons. Adult P. volitans can easily reach 15" in length and should not be kept in tanks smaller than 75 gallons. I have read many posts from people who have kept these fish in far smaller tanks, so my advice to them is to be prepared to provide a larger tank within a year or so, as this is the time required for these fish to reach adult size.

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Figure 2. Lionfish like this Dendrochirus sp remain under 7" and can be easily kept in a 55 gallon tank. Photo by Frank Marini.

Requirements for aquascaping can vary between species; almost all lionfish are dawn/dusk predators and will spend much of their time during the day lounging and hiding. The Antennata and Radiata lions will hide almost exclusively during daylight hours, so caves and covered rockwork are useful, while Volitans lions prefer open waters day and night. Dwarf lions initially will hide during the day; however, once acclimated they will spend much of the day light hours in open view. Juvenile fish of all lionfish species are quite timid and spend daylight hours hiding in the rockwork. The good news is that most lionfish will acclimate to tank life and your individual lighting schedule, so after a few months of hiding and lounging, they will begin to spend much of their time out in the open. According to Michaels (1998), lionfish are ideal candidates for reef aquariums. While I agree that these fish won't harm any corals, they limit tankmate selections [Figure 3]. If a reef tank has no fish equal to or smaller than the lionfish, no ornamental shrimp or crabs, then lionfish are acceptable. I would say that housing a lionfish in a reef is your decision, as I have seen both beautiful reef tanks with dwarf lionfish as occupants, as well as a reef tank with no other fish life than a Volitans lionfish.

Figure 3. Lionfish in a reeftank? Sure, it can be done, and the dwarf lionfish make a great addition, just be aware that they will eat any small fish or moving invertebrate that they can fit into their cavernous mouths. Photo by Frank Marini.

The Line-up of Lions: Common Lionfish Species
(listed by increasing size)

  • Dwarf Lionfish - Dendrochirus sp.

Dendrochirus biocellatus
Common name: Fu Man Chu lionfish
Maximum size: 5-6 inches, minimum tank size: 30 gallons

Commentary: The Fu Man Chu lionfish is a diminutive lionfish that can be readily identified by two large whiskers that protrude from either side of its mouth [Figure 4]. The fish is red-orange with blackish specks. The two solid pectoral fins resemble fans from a Spanish Dancer, and are circular with the lower fin rays forming angular points. This fish is a poor swimmer; instead, it tends to scurry across the substrate and will occasionally hop. Out of all the lionfish I have kept, Fu Man Chu's are one of the more aggressive lionfish towards same species fish. I have not been able to introduce two Fu Man Chu lions in my 180-gallon tank without one Fu harassing the other to the point of sickness. What is remarkable with Fu Man Chu lionfish is their prey stalking behavior. Once a prey item has been identified, the fish will approach and begin to shake its head and gill covers from side-to-side [Figure 4a]. When in capture range of the food item, the lionfish will begin to rhythmically twitch its dorsal spines back-and-forth, and as it readies to gulp the prey item, it vibrates the lower portions of its pectoral fins [Figure 5].

The Fu Man Chu lionfish is one of the more difficult lionfish to keep in the home aquarium because they ship very poorly and they don't readily wean from live to prepared foods. These fish are among the most shy and cautious lionfish I have ever owned, and it is imperative that caves and hiding spots are made available for this fish to hide. Initially, they spend much of their time hiding in the rockwork and will only come out to feed. These fish will have problems competing with fast swimming fish for food, and unless they are target fed, will starve. Live ghost shrimp should be among the first foods offered to establish this fish onto an aquarium diet, and once it is comfortable and begins coming out from hiding, the aquarist can begin to wean the fish onto prepared foods. I have had great success using Piscine Energetics Mysis shrimp as an enticing prepared food by simply thawing the frozen Mysis and squirting it out of a tube in front of the hungry Fu Man Chu. Over the years, I have kept three Fu Man Chu lionfish, and it took over two months to wean the slowest one from live foods.

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Figure 4. A side view of a Fu Man Chu lionfish. Notice the two "whiskers" that distinguish this lionfish. Also, notice their unique coloration; no other lionfish possess this much orange. This picture is typical of a Fu Man Chu lionfish, slithering on the rockwork. These fish walk more often than they swim. Photo by Frank Marini.
Figure 4a. Shown here is the second dorsal fin and its twin eyespots which identify the "biocellatus" or two eyes. The Fu Man Chu will vibrate this fin in the hope of distracting and confusing potential prey and predators. Photo by Frank Marini.

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Figure 5. A Fu Man Chu lionfish heading into the rockwork to hide for the day. Photo by Frank Marini.

Dendrochirus brachypterus
Common name: Dwarf fuzzy lionfish
Maximum size: 7-8 inches, minimum tank size: 30 gallons

Commentary: The Dwarf fuzzy lionfish is probably the best of the dwarf lions that a hobbyist can keep in an aquarium, mainly because they are hardy, disease resistant, readily weaned onto prepared foods, and are actively swimming lionfish. These fish have a unique fuzzy texture to their scales and possess semi-circular pectoral fins that are decorated with stripes and patterns. The fin rays are short and connected with solid webbing. During the day, D. brachypterus tend to hang upside down in caves or on soft corals. During the dawn/dusk periods, dwarf fuzzy lionfish become very active and swim about in search of food. After a few months in captivity, all of my dwarf fuzzy lionfish have learned to swim towards me whenever I walked into the room, and they continue to swim and beg for food while I'm present [Figure 6].

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Figure 6. A dwarf fuzzy lionfish. This little lionfish has learned to beg for food, and when he sees me come into the room, he immediately rushes to the top of the tank and spits water out the top. Photo by Frank Marini.

Dwarf fuzzy lionfish come in three-color varieties: drab brownish [Figure 7], beautiful reddish [Figure 7a], and a rare yellow form [Figure 8]. Of course, combinations of reds and yellows and browns and reds exist as well. The most common in fish stores are the brown/reds and the brown/drab yellowish. However, I have seen a few solid red Dwarf fuzzies and I did find two solid yellow Dwarf fuzzies in the past 10 years. Adult male Dwarf fuzzy lions are readily identified by having a larger head, longer pectoral fins (the fin tips reach past the caudal peduncle), and have between 6 to 10 bands (or stripes) on their pectoral fins. Female Dwarf fuzzy lionfish have only 4 to 6 stripes. In the wild, Dwarf fuzzy lions live singly or in groups of three to 10 individuals, but in a large home aquarium (100 gallons or greater) it is possible to keep a large dominant male and several females. I have kept a trio of Dwarf fuzzy lionfish for many years, and my male would routinely breed with a female. In smaller tanks only one specimen is recommended as Dwarf fuzzy lions will harass conspecifics within a size-limited tank habitat. Out of all the lionfish species, Dwarf fuzzy lionfish might be the best suited for a reef tank; they have small mouths, don't usually bother similarly-sized fish, and tend to stay to themselves.

Shown here is a Japanese lionfish Dendriochirus bellus. This cold-water lionfish is very similar to the dwarf fuzzy lionfish, and occasionally makes its way into the U.S. aquarium trade. Photo courtesy of H. Uchiyama (http://www4.justnet.ne.jp).

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Figure 7. The brownish drab coloration of a typical dwarf fuzzy lionfish. Notice the blue eyes and band patterns on the pectoral fins. Of importance is that its pectoral fins stops well before the caudal peduncle and has fewer than six defined bands. Photo by Frank Marini.

Figure 7a. A solid red dwarf fuzzy lionfish. While not as common as a solid brown lionfish, these red lions do occassionally appear at the local fish stores. Photo by Frank Marini.

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Figure 8. The rare yellow form of a dwarf fuzzy lionfish. According to Michaels, this color morph is located in one central location: the straits of Lembah. This fish commanded a $350 USD price tag. Photo by Frank Marini.

Dendrochirus zebra
Common name: Dwarf lion or Dwarf zebra lion
Maximum size: 6-8 inches, minimum tank size: 30 gallons

Commentary: The Dwarf lionfish are beautiful lionfish in a small package. These little lions are among the most common lionfish found in the hobby. Dwarf lions are characterized by a dark spot on the lower portion of the gill cover operculum, and concentric bands on the inner portion of the pectoral fins. The pectoral fin membranes extend almost all the way to the fin ray tips, and form a solid web. The body pattern consists of alternating dark brown and light brown stripes. This species demonstrates very subtle sexual differences, and in my experience is impossible to sex by appearance. Husbandry of a Dwarf lion is exactly the same as keeping a Dwarf fuzzy lionfish. The most important points are providing the fish with plenty of good hiding spots, providing a nutritious and varied diet, and maintaining good water quality [Figure 9].

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Figure 9. Face-on with a dwarf zebra lionfish. Notice the broad striping patterns which identify this species. Photo by Frank Marini.
  • Medium-bodied Lionfish - Pterois sp.

Pterois antennata
Common name: Antennata lion, Spot-finned lion
Maximum size: 8-9 inches, minimum tank size: 55 gallons

Commentary: Antennata lions are a hardy, medium-sized lionfish for the home aquarium. Antennata lions are beautifully marked with alternating vertical bands of reds, whites, and browns, and are readily identified by their pectoral fins which possess webbing that connects only halfway up the fin ray [Figure 10]. This membranous area has one or more dark spots resembling eyespots. The posterior portion of each fin ray is whitish and extends to past the caudal peduncle on the ventral portion of the pectoral fin; each fin ray is independent and not connected by webbing [Figure 10a]. There are no readily identifiable sexual markings on these fish. In the home aquarium Antennata lionfish are shy and will spend a lot of their initial time in the tank hiding. If multiple Antennata lions are present, the aquarist will need to ensure that each has its own hiding spot. In my experience, these fish prefer shrimp over fish for food, but are readily established on ghost shrimp first, then weaned onto prepared foods using Piscine Energetics frozen Mysis or whole krill.

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Figure 10. An upside-down P. antennata lionfish. Using the pectoral fins as a guide, one can identify antennata lionfish. Notice the single row of spotting nearest the pectoral base, and the membranous connection, which terminates less than 1/2 the way up the fin rays. Photo by Frank Marini.

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Figure 10a. A P. antennata lionfish in motion. Again, notice the single row of spotting on the pectoral fins, a trait which helps identify this species. Photo by Frank Marini.

Pterois mombasae
Common name: Devil lionfish, Mombassa lion, deepwater lionfish
Maximum size: 7-8 inches, minimum tank size: 55 gallons

Commentary: These deep-water lionfish are found mainly on South African reef slopes. They are usually found inhabiting sponge and soft coral beds in search of food, and feed almost entirely on crabs. Devil lions are almost always misidentified at the fish store as Antennata lions [Figure 11]. Four main characteristics distinguish them. First, Devil lions have larger eyes and, in fact, the eyes look out of proportion to the head. Second, the vertical striping patterns on Mombassa lionfish are red or deep reddish with a unique texture to the pattern, almost fuzzy looking. Third, the lower portion of the pectoral fin on a Mombassa lion has three or 4 fin rays that are webbed [Figure 11a]. This is not the case in Antennata lions. Fourth, the pectoral fin of a Devil lion has multiple eyespots throughout the fin, not just around the attachment, as in Antennata lions. The care of Devil lionfish is similar to that of Antennata lionfish. I have found Devil lions to be intolerant of harassment by any fish, although they may swallow any fish smaller than them and they are particularly intolerant of poor water quality. These fish are often the first fish to succumb to bacterial infections that effects their eyes (resulting in a cloudy-eyed appearance) as water quality declines.

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Figure 11. One, two, three, mombasse!… Looking deep into the eyes of a devil lionfish. In this photo you can readily distinguish a striping pattern different than an antennata lion, a finely textured pattern. Also, notice the large prominent eyes. Photo by Frank Marini.

Figure 11a. Peering out of some rockwork, this P. mombasse looks around inquisitively for food. Again, the large wide eyes are prominent in this photo. Also notice there are multiple rows of spots at the base of the pectoral fins. Photo by Frank Marini.
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Pterois radiata
Common name: Radiated lion, Clearfin lion
Maximum size: 9-10 inches, minimum tank size: 65 gallons

Commentary: Radiata lions are found primarily in the Red Sea, and in my experience, they ship poorly to the wholesalers and pet stores, possibly because of their remote location in the wild. So, finding a good healthy Radiata lion can be difficult. These lions are also considered rare in the wild, are therefore not frequently seen in the lionfish trade, and they subsequently command a higher price. In my opinion, they are among the more beautiful lionfish, as the markings and patterns on them are so variable that they are almost chameleon-like [Figure 12]. The body markings consist of alternating wide vertical bands of dark red, browns, black-reds, red-greens, all separated by a sharp white stripe. The caudal peduncle has two vertical bands that point toward the tail fin [Figure 12a]. The second dorsal, anal and caudal fins are clear and without spots or markings. The pectoral fins are spectacular white rays with membranous webbing only on the bottom quarter. When Radiata lionfish swim, they extend their pectoral fins, accentuating the white stripe pattern. In the home aquarium, Radiata lionfish are one of the more difficult lionfish to keep for a number of reasons. First, they usually arrive at the fish stores in poor condition. Second, they are passive lionfish and do not compete well for food against any fast swimming tankmates. Third, they are intolerant of poor water quality and often succumb to illness as water quality declines. Fourth, I have found these lions to prefer to eat shrimp and crabs over fish, and I've had to establish them using ghost shrimp and small fiddler crabs as first foods [Figure 12b]. Once they are established on these foods, however, it is difficult to get them to accept prepared foods, but with patience, they may accept other foods and will survive quite well in the home aquarium.

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Figure 12. A P. radiata lionfish on display. This photograph does wonders to demonstrate how the large body stripes of a Radiata lionfish are interspersed with white lines. Radiatas have 2 large single ocular projections and no lower lip projections. Also, notice the pectoral finnage on this species; the rays are connected with a curved red membrane. Photo by Frank Marini.

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Figure 12a. This photograph demonstrates the beautiful color patterns of Radiata lionfish. Notice the long sweeping pectoral fins and note the 2 vertical stripes on the caudal peduncle. These two stripes are found on all Radiata lionfish. Photo by Frank Marini.

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Figure 12b. An adult Radiata lionfish, seen here in an upside-down position. This 10" fish is both large and in charge of the tank. Lionfish are underwater acrobats and will swim in any, and all, directions to acquire food. Photo by Frank Marini.
  • Large-bodied Lionfish - Pterois sp.

Pterois russelli
Common name: Russell's lion
Maximum size: 10-12 inches, minimum tank size: 75 gallons

Commentary: One of the smaller members of the Volitan lionfish group, Russell's lionfish are hardy, pollution tolerant lionfish for a medium to large aquarium [Figure 13]. In the wild, Russell's lionfish are found in coastal South African waters near silty mud flats and estuaries, where they feed primarily on small fish and crustaceans. Russell's lions are one of the more commonly available lionfish in the hobby, and are frequently misidentified as "red Volitans". Juvenile Russell's lions have a whitish body with dark brown vertical stripes [Figure 13a]. The pectoral fins are pale white with light brown and blue spotting. As the animal grows and ages, the body pattern becomes more diffuse and turns rust-brownish in color, while the pectoral fins turn darker and lose the spotting. The second dorsal, anal, and caudal fins are clear with an occasional brown spot. The head features two ocular projections and a few lower tassles that hang off the mandible.

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Figure 13. A Russell's lion. Once you know the color pattern of Russell's lionfish, you will never make the misidentification of a Volitans again. Russell's lionfish have spot-free clear fins, and their body patterns are white with large infrequent stripes. Photo by Frank Marini.

As aquarium residents, Russell's lions adapt easily and quickly to aquarium life. They almost always wean to prepared foods, only requiring a few days of starvation to entice them to eat a "wiggling" silverside or chunk of krill. Russell's lions spend almost all their time out in the open and will often swim boldly with other tankmates in search of food. I have found these fish to grow fairly quickly when fed properly, and they will easily become 10 inches long within one year [Figure 13b].

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Figure 13a. A juvenile Russell lionfish, similar to what is commonly seen at local pet stores. This little 4 inch juvenile possesses long flowing pectoral fins and will grow into a foot-long fish eater within one year. Photo by Frank Marini.

Figure 13b. The same lionfish 1 year later. Sure, I feed them well, but look how big they get. Russell's lions are eating machines, and will easily outgrow a 55 gallon aquarium within 8 months. If you noticed that the body of this fish is getting thicker and the pectoral fins are appearing shorter, you are correct. Older Russell's lionfish have fat, squatty bodies and relatively short pectoral fins. Photo by Frank Marini.
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Pterois volitans
Common name: Volitans lion, "lionfish", turkey fish
Maximum size: 12-15 inches, minimum tank size: 85 gallons

Commentary: When someone states they have a lionfish, this is usually the fish they are describing [Figure 14]. The most common lionfish in the hobby, the Volitans lionfish are hardy and pollution tolerant lionfish that are great inhabitants for a large aquarium. In the wild, Volitans lions spend dawn/dusk periods in open water in search of foods (primarily fish), and frequently travel in packs of multiple animals (5 or more). During the daylight hours, they head to cave openings and protected structures for safety.

The coloration of Volitans lions is both variable and attractive. These fish are generally sold in two color morphs: a red form with reddish/brown stripes [Figure 14c], and a black morph, with black markings [Figure 16]. The amount of black or red varies with the collection locale of these fish, and even solid black Volitans have been seen at my local fish stores. Juvenile Volitans lions have wonderful busy vertical stripes alternating with lighter and white outlines [Figure 15]. The pectoral fins are disproportionately long; each ray is individually webbed, and the center of the pectoral fin is frequently clear. As these fish age, the striped body pattern becomes more diffuse and the pectoral fins "appear" to shorten, resulting in a squatty large-bodied fish with short fins.

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Figure 14. A juvenile P. volitans lionfish. This is the typical dark brown (red) color morph. The striping pattern varies on almost all of these fish. What is noteworthy is that the center of the pectoral fins is almost translucent. Also, Volitans lionfish have multiple mandibular projections, and two ruffled ocular projections. Photo by Frank Marini.

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Figure 14c. The same lionfish, pictured one year later. Like the Russell's lionfish, P. volitan lionfish grow like weeds. This 13" long fish is a Hoover in lionfish stripes. The pectoral wingspan on this fish reached over 18" wide, hammering home the point that Volitans lionfish require big tanks. This fish can easily consume any medium sized angel, wrasse, or dwarf lionfish. Photo by Frank Marini.

In the home aquarium Volitans lions make beautiful and interesting "centerpiece fish." Frequently offered for sale as 2 inch juveniles, they are cute and adorable with tremendous personality. Juveniles are active swimmers and are constantly searching out food. Volitans lions almost always wean over to prepared food quite well, usually with no more assistance required than adding shrimp or fish chunks to the water column. Volitans lions are aggressive feeders and will actively compete with other fast swimming fish like tangs and wrasses. These fish are pollution tolerant and are the most hardy and forgiving of the aquarist's negligence of all lionfish. The main problem with Volitans lionfish is their size; the cute 2" juvenile fish at the store will reach 8-10" in one year's time (with proper feedings) and within 6 more months it will obtain a maximum size of 15". These fish easily outgrow their tankmates and will frequently eat them. Any fish that is equal to half the body size of the Volitans lion, is considered food, and will be eaten in time. Additionally, a 15" long fish with a large pectoral fin span requires a large aquarium, and even though these fish tend to be more sedentary as adults, they still need to turn around, so an 18" wide tank is recommended at a minimum.

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Figure 15. A P. volitans perched on the rockwork. Unlike many of the dwarf lionfish, Volitans lionfish will spend much of their time out in the open searching for food. Photo by Frank Marini.
Figure 16. A headshot of a black "morph" of P. volitans. This adult lionfish has lost its juvenile ocular projections and has taken on a large bulldog-like jaw line. Photo by Frank Marini.

Nutrition

The biggest challenge faced by a lionfish owner is providing a proper nutritious diet. Of all the problems I see with lionfish, improper nutrition and its results are the predominant health issue for captive lionfish. In the wild, lionfish eat smaller fish and invertebrates. Unfortunately, in the home aquarium lionfish will readily accept live wiggling feeder fish like feeder goldfish or rosy red minnows. The reason this is a problem is that only freshwater feeder fish are available to hobbyists and they do not provide the proper nutrition. In fact, a lionfish fed exclusively with goldfish will frequently die prematurely due to a number of feeder fish-associated problems. A study by Toonen et al (Toonen, 2000) demonstrated that freshwater feeder fish of the carp family (like goldfish, rosy reds, etc.) are very high in fats and lack all the marine based highly unsaturated fatty acids (HUFAs) required for proper health of marine fish. Of all the freshwater feeding choices available to the hobbyist, ghost shrimp are the best of what's available. Ghost shrimp can be enriched in marine-based HUFAs by being fed any marine flake food or marine plant material, and I have not found a lionfish yet that will ignore a ghost shrimp. The best way to ensure a lionfish remains in proper health is to feed it a varied diet of fresh and frozen seafoods. With that said, I would recommend to anyone keeping a lionfish to establish the fish in the aquarium by temporarily using freshwater feeders such as ghost shrimp, guppies, mollies, rosy red minnows, and goldfish for 2 weeks up to 1 month maximum. After this establishment period, the lionfish must be weaned off these feeders and onto marine-based prepared foods.

However, this is where another problem begins. Most lionfish require their food to "look" alive for them to eat it, and this wiggling motion by potential prey items triggers their innate feeding response. One of the better methods to wean lionfish onto prepared foods is to starve the fish for 3 or 4 days, then introduce a small intact lancefish or "silverside" (this is a saltwater minnow packaged in 25, 50, or 100 packs and commonly available at most local fish stores). I find it best to impale this silverside onto a clear acrylic rod (the feeding stick) and "wiggle" it away from, but in full view of the lionfish [Figure 17]. The key point is that you have to convince the lionfish that this dead food is actually alive. Some people impale the silverside on a chopstick, or use their fingers (I do not recommend this method) and wiggle it. Once weaned onto prepared foods, I recommend rotating through many marine based foods, such as chopped gulf shrimp (with their shell on), lobster tail, crabmeat, strips/chunks of marine fish (available at the grocery store), and chunks of squid and octopus. I also recommend supplementing these foods by adding a few drops of a vitamin (such as Zoe™ or VitaChem™), and marine HUFA boosters like Selcon™ or Zoecon™.

It may take time to encourage a lionfish to eat non-living foods, but this weaning process is the most critical key to success in lionfish husbandry. In my experience a "hungry lionfish is a brave lionfish," and the use of starvation prior to offering prepared foods is often a key to success. If feeding live foods is desired, grass shrimp (harvested from saltwater), fiddler crabs, small shrimp or saltwater harvested minnows are good choices. Additionally, it is usually easier to get a younger lionfish to switch over to non-living foods than an older animal.

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Just being lazy, hanging about on a rock. This is a typical pose for a lionfish while they are resting, digesting or waiting for food. Photo by Frank Marini.

After being weaned onto prepared foods, these fish often learn to beg for food. Try to avoid the temptation to overfeed. Lionfish are gluttonous and, if fed continuously, will grow too quickly (possibly resulting in health issues and a shortened life span) and generate undesirable amounts of waste in the tank water.

It is important not to offer a lionfish large prey items, or large chunks of food, as reports have suggested that lionfish have been killed by food rotting in their gastrointestinal (GI) tract. According to Michaels (1998), lionfish will occasionally kill themselves due to overeating. While I have not experienced this, I have found that lionfish will eat to the point of regurgitation, and even this sign of overeating should be avoided. Problems with overeating can be avoided by offering multiple smaller food items, rather than one large one. In fact, if a lionfish is given the choice between a large fish and many small ones, it will normally choose to eat the smaller fish first. In the wild, a lionfish will consume from 1 to 11 small to medium-sized prey items per feeding, then retire to a hiding spot to digest the food for a day or so, and repeat this process. Therefore, I would recommend feeding lionfish to the point of seeing a small bulge in their abdomen two to three times weekly. I also recommend starving lionfish for a few days to accurately recreate their natural dietary intake and, in fact. a 3-feedings/week schedule is sufficient to ensure proper growth.

Figure 17. The weaning basket. This basket is placed in the tank and protects newly acquired scorpionfish from the other fish, while I train them to eat prepared foods. Utilizing the basket, I can keep a watchful eye on the feeding of my new fish, as well as acclimate the fish to my tank and its tankmates. I have found the weaning basket to be a key in allowing a stubborn new fish the time it requires when feeding in a hostile environment. You can see in the basket that I have acquired another Yellow Dwarf fuzzy lionfish. Unfortunately, this one is another male. Photo by Frank Marini.

Those Beautiful Fins

Lionfish are hunters and ambush predators, plain and simple. Because they hunt, they have adapted their body shapes to facilitate their prowess. One of the most remarkable features of lionfish are their pectoral fins. These fins may vary in size, but are flamboyant, colorful, and very mobile. When a lionfish stalks it's prey, it uses the pectoral fins to perform a number of tasks, often swaying its pectoral fins from side-to-side and slightly forward, an action which seems to make its approach less distracting to the intended victim [Figure 18]. Additionally, by tilting the fins forward, it creates a barrier or fencing, and herds the prey to a certain spot restricting its movement. As the lionfish moves in closer, preparing to swallow the food item, the pectoral fins are frequently tilted and shaken (most likely to distract the prey and, just as importantly, to allow the lionfish to focus on the eye of the food). Large Volitans lions will often drag their pectoral fins across the bottom of the aquarium, with the hope of flushing out any hiding food items. Similarly, in the dwarf lionfish species, the fin movements are frequently exaggerated when hunting. Members of the dwarf fuzzy lionfish twitch their dorsal and pectoral spines when hunting. Fu Man Chu lionfish have a unique rhythmic sequential back-and-forth twitching of their dorsal spines, and they vibrate only the ray tips of their pectoral fins when hunting prey items. The dorsal spine movements are thought to distract and confuse prey and enhance the lionfish's hunting ability. Most lionfish are brightly colored under the lighting of the home aquarium. However, in low-light situations, like those found at dusk and dawn, the brightly colored markings become dark disruptive patterns that serve as a camouflage, making the lionfish less visible to potential prey. The pectoral fins also serve another purpose: when threatened by a predator, a lionfish will often spread these fins widely, orient its head facing down to aim its venomous spines forward, and presents a formidable and menacing target to the attacker. In a few lionfish species, the inner pectoral fins have boldly marked eyespots and, when displayed, these eyespots may scare off or confuse potential predators.

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Figure 18. The backside of a dwarf fuzzy lionfish. What you can see here is that the lionfish has flared its fins in response to feeding. These lionfish use their pectoral fins to herd and trap their prey. Photo by Frank Marini.

Compatibility

One of the most common questions I address is, "What else can I keep with my lionfish?" The answer is a complicated issue [Figure 19]. Frequently, hobbyists want to keep multiple lionfish in the same aquarium, and although there is no problem housing two or more of these fish together, closely related lionfish will fight. I have found this problem occurring most frequently with the dwarf lionfish, in that Dwarf Fuzzy lionfish will often harass Dwarf Zebra lions. Although these skirmishes are often nothing more than gill cover flaring, head shaking, and chasing, many times it's accompanied by a bite or two. If one lionfish persistently attacks another, they should be separated or the subordinate lionfish will cease feeding and may die. Another point of consideration when keeping both large and dwarf forms of lionfish together is that large lionfish will eat smaller lionfish, and I have personally witnessed this on several occasions.

Figure 19. Potential tankmates for lionfish. I find that planktonic feeding triggers, large tangs and a few larger fish (like the Jewel damsel) make suitable tankmates for lionfish. Once you have a tank full of lionfish, you'll wonder why the tank looks so empty. Nobody's swimming. Inevitably, you'll want a few swimming fish. Photo by Frank Marini.

Special considerations need to be used when selecting tank mates for lionfish. Lionfish will eat any small fish or crustacean that fits into their cavernous mouths. Even though lionfish are venomous, lionfish are not immune to being harassed or even eaten by other fish. Large eels, frogfish and other scorpion fish are all predators of lionfish in the wild. According to Michaels (1998), large angelfish, pufferfish, and triggerfish are also known to harass lionfish. Triggerfish are notorious for nipping off the dorsal spines before killing lionfish. However, I have found the planktonic feeding triggers (Blue cheek, Pink-tailed, Niger) to behave more predictable towards lionfish, and I would consider them compatible tankmates. Because of the small confines of many aquariums, lionfish have been known to impale tankmates with their venomous spines. Envenomation likely occurs for several reasons: the lionfish may be retaliating for a prior attack and intentionally impales the fish, or a tankmate accidentally swims into the venomous spines. When jabbed by a lionfish spine, the victim will usually develop a good size lesion at the point of impalement and the area will become inflamed, reddened, and necrotic. Other signs of the venom on impaled fish are increased breathing rates, distress, color loss and decreased swimming. In many instances, death will occur. According to Michaels (1998), most fish injected with a large dose of lionfish venom (more than what is injected with just one spine) will die with 30 minutes.

Diseases and Health Problems

Lionfish are hardy fish, and if fed well and provided with good water quality, almost never contract diseases or parasites. It is important to note that a thin membranous lining called a cuticle covers lionfish. Since lionfish are sedentary fish, the cuticle is used to protect the lionfish from settling organisms. In fact, lionfish will occasionally shed their cuticle to remove any unwanted hitchhikers. A shed cuticle looks like a large mass of whitish stringy mucus, and this shedding occurs when a lionfish just start flashing around the aquarium, trailing white stringy mucus behind it. Cuticle shedding is also a sign of improper health in lionfish, as stressed lionfish or lionfish kept in poor water quality will increase shedding behavior. The most common disease problems I have seen are fin rot (a bacterial infection which is treated with antibiotics), cloudy eyes (also a bacterial infection) [Figure 20] and dinoflagellates. Lionfish do get ich, and this condition can be treated with hyposalinity or copper based medications. As far as other health issues, the major problems I have observed are starvation and lockjaw. Both occur suddenly, and usually in an established fish that has adapted well to captivity. In regards to the issue of starvation, the lionfish just stops feeding, and over a few weeks period cannot be enticed to eat by either live or prepared foods. Starvation is usually a result of long-term improper diet caused by the exclusive feeding of one type of food (freeze-dried krill is generally the most common cause because it's widely available and convenient). This diet can potentially cause a blockage of the gastrointestinal tract, or result in a nutritional deficiency, or result in the formation of a goiter. Lockjaw occurs when the lionfish's mouthparts stay fixed in the open position. I have observed this on many occasions. It is unclear what causes this problem, but I have observed lionfish unintentionally ingesting substrate during feeding or banging their mouthparts into rockwork when hunting food items and this may account for part of the problem. Over the course of a few days, fish with this condition were able to work their jaws closed again, but the alignment of the jaw was never perfect in any case, and their jaws would frequently dislocate.

Figure 20a. A P. mombasse with severely cloudy eyes. Sadly, the Mombasse lions are quite sensitive to deteriorating water quality, and are the proverbial "canary in a coal mine". These cloudy eyes can be successfully treated with an antibiotic regimen. Photo courtesy of buddamonk.

Lionfish Stings

All members of the family Scorpaenidae possess venom glands in their dorsal, anal, and pelvic spines. The primary function of these spines is a defensive measure against conspecific threats and predators. The amount of venom injected from each spine is dependent on how much pressure is being placed on the spine and the amount of time the spine is left in the tissue. In the home aquarium, lionfish stings are very rare, but do occur. In fact, there are three main events in the normal course of owning a lionfish that may increase the chances of being stung. The first occurs when the lionfish is transferred from a shipping bag, or when transferring the lionfish from one tank to another. The reason your incidence for getting stung is high here is that you are maneuvering around a lionfish that is close to your hand. The lionfish will often be exposed and may thrash around in defense, or might fall out of one container to the next, with an inadvertent sting as a result. The second most common activity that increases the likelihood of getting zapped by a lionfish occurs while cleaning the tank. While the lionfish won't rush towards you or race across the aquarium, the act of putting your hands into the lionfish's environment serves to put it on alert. They will often hide under the very rockwork being rearranged or the glass being cleaned nearby. Being a quite curious fish, they might also think you are introducing food, and they may hover nearby. Lastly, through some unfortunate event, you might trap or corner a lionfish in the tank, and cause the lion to become defensive.

Shown here is another Japanese lionfish called Paraterois heterura. This unique lionfish has caudal rays which extend into long finnage. This fish is similar in size to P. antennata. Photo courtesy of H. Uchiyama (http://www4.justnet.ne.jp).

Getting Stung... It Can Happen To You

In general, lionfish are fairly peaceful fish that are not really interested in the mundane tasks of an aquarist cleaning the tank or doing water changes. However, there can be exceptions. One day I was cleaning my tank, vacuuming the substrate, moving the rockwork around and, apparently during this time, I was wiggling my fingers. All my lionfish (and scorpionfish), are trained to take silversides and meat strips when I wiggle the food in front of them, so I assume a few of the fish were coming over to consider if my fingers were food. I initially just shooed them away, but one of them was persistent and kept coming back. At one point, I was contemplating where to place the next rock and not really paying attention to the task, but my hand and arm were submerged, and I felt something brush my arm. Reflexively, I jerked my hand back, and this sudden movement spooked the lion sufficiently for him to immediately point head down with his dorsal spines extended. I impaled myself onto his outstretched spine. I immediately pulled my hand out, looked at where the spine entered ("Whew, no blood!"), and continued cleaning the tank. After about 30 seconds, I realized what was happening. A pain started throbbing around my hand, up to my wrist, and then stopped. At first, it was like a bee sting in intensity, and the pain increased for another 5 minutes. At that point, it felt like a bee sting on steroids! This happened back in 1990, when there was little, if any, knowledge on what to do for a lionfish envenomation. I rushed to the emergency room (concerned mainly by what I had read online about lionfish stings and their venom). I was very scared, and what made matters worse was that the doctor had never heard of a lionfish, or a scorpionfish! Since the physician had little idea what to do, he treated the wound like a wasp sting. He rubbed the area with a strong corticosteroid solution, and put me on a strong antihistamine. The pain lasted for about 20-30 minutes; my hand throbbed and ached, even burned at times. My hand suffered from numb areas for about 3 days after this event.

Stupidly, I have been stung two more times since then, and each time it was 100% my fault. I found that just reaching into the tank and grabbing an overturned rock could yield a hiding lionfish. I can tell you from experience that you don't want this to happen twice in your lifetime, and you definitely don't want it to happen 3 times in 12 years! So my advice is, "don't get stung!" Pay ultimate respect to these fish at all times, and whenever you perform any task in your tank, know where your lionfish are at all times and be wary of them.

Lionfish Sting... What To Do

If a lionfish or scorpionfish ever stings you, the very first thing to do is immerse the wound site in hot, non-scalding water (110-113°F) for 20 to 30 minutes, or until the pain subsides. According to Michaels (1998), applying rapid heat using a hair dryer will also work. The key point is heat; lionfish venom contains many heat labile proteins, and heat will denature these venom proteins, preventing them from spreading in the bloodstream and decreasing the severity of their effects. Do not use boiling hot water; the burn resulting from boiling water will often be worse than the lionfish sting. The most frequent symptoms of a lionfish sting are pain and swelling. However, a few people may have an allergic reaction to lionfish venom and should be cautious if the pain and swelling get worse over a few hours. More detailed information on envenomation may be found in James Fatherree's article located here in this issue.


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Another wonderful dwarf lionfish Dendriochrius barberi. This uncommon dwarf fuzzy lionfish makes a great little display animal. Readily identified by its glowing red eyes (unlike most Dendrochirus brachypterus that possess blue eyes), this species requires the exact same husbandry as its common Dwarf fuzzy brother. Photo courtesy of Chris Smallridge (T-T-Trigger).

Conclusion

Often considered the ultimate showpiece in a fish-only tank or as a novelty in a reef tank, lionfish have established a place in our home aquariums. The different sized species allow any hobbyist to care for a lionfish in almost any sized tank, and to sense the mystical "coolness" of lionfish. Owning a lionfish entails certain responsibilities, and these can be met by following a few key steps to success: provide a proper varied diet, compatible tankmates, and good water quality. It is also important to respect these fish at all times and be aware where they are when placing one's hands in the tank. Once you've decided to commit to and care for a lionfish properly, you'll be rewarded with the thrill of seeing one of the oceans top predators in action. These fish are long-lived and take on a dog-like personality; the ultimate "Rover" armed with venom.

Talk about a rare lionfish... this is the Ambon lionfish, a furry lion which utilizes its "fur' to hide amongst the plant life. Fortunately, this rare lion never makes it into the hobby. Photo courtesy of Jeff Rosenfeld of The Vibrant Sea.

Shown here is Neosebastes entaxis, another rare lionfish. These lionfish are found only in waters off of Japan and are seldom collected for the U.S. Photo courtesy of H. Uchiyama (http://www4.justnet.ne.jp).



If you have any questions about this article, please visit my author forum on Reef Central.

Additional Reading:

Wet Web Media - Excellent articles by Robert Fenner on lionfish and their relatives.

Coral Realm

Fishbase

References:

Burgess, W.E., et al. 1991. Dr. Burgess's Atlas of Marine Aquarium Fishes 3rd Ed. T.F.H. Publications. Neptune City. pp. 114 - 122.

Eschmeyer, W.N., 1986 Scorpaenidae. In M.M. Smith and P.C. Heemstra (eds.) Smiths' sea fishes. Springer-Verlag, Berlin. pp. 463-478.

Michael, S. W. 1998. Family Scorpaenidae. Reef Fishes Volume 1. Microcosm. Shelburne. pp. 453 - 489.

Michael, S. W. 1999. Scorpionfish. Marine Fishes: 500 + Essential-To-Know Aquarium Species. Microcosm. Shelburne. pp. 63 - 69.

Toonen, R. Fish Nutrition. http://www.reefs.org/library/article/r_toonen6.html

 




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The Lionfish Info Sheet: Captive Care and Home Husbandry by Frank Marini, Ph.D. - Reefkeeping.com