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antipodi
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Tue Mar 07, 2006 1:03 am
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 Lionfish ..Care and Breeding
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Lionfish ..care and breeding
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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).
For a start 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 Acquariums 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 common names 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
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. 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.
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 these fish won't harm any corals, they limit tankmate selections. If a reef tank has no fish equal to or smaller than the lionfish, no ornamental shrimp or crabs, then lionfish are acceptable.
Housing a lionfish in a reef is your decision, both beautiful reef tanks with dwarf lionfish as occupants, as well as a reef tank with no other fish life than a Volitans lionfish.
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.
Nutrition
The biggest challenge faced by a lionfish owner is providing a proper nutritious diet. Of all the problems 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, it is recommended 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). It may be 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 . 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 (It not recommended.. this method) and wiggle it. Once weaned onto prepared foods, It is 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.Also supplement 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.
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. It is known 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,it is recommended feeding lionfish to the point of seeing a small bulge in their abdomen two to three times weekly. It is suggested 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.
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. 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.
Compatibility
One of the most common questions asked is, "What else can I keep with my lionfish?" The answer is a complicated issue.
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. The problem occurs 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.
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Potential tankmates for lionfish. 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.
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. Planktonic feeding triggers (Blue cheek, Pink-tailed, Niger) to behave more predictable towards lionfish, and consider them as 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) 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. It is unclear what causes this problem, but it has been 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.
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..
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.
Here is a Breeders story.
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.
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.
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