Pterois volitans (Lionfish)  

Dangers:

Are Lionfishes poisonous? Nope; in fact they're quite delicious, cooked or raw. Venom refers to materials that are toxic to the touch, poisoning generally comes about from ingestion. These fishes are venomous, they are not poisonous.

To illustrate this point, I was shocked one day while wholesale fish shopping with one of our aquarium service company's employees when he nonchalantly pulled a dying lionfish from a tank, pulled it's skin off, tail to head, and promptly chewed the muscle off. Leif had been a Peace Corps volunteer in Samoa, helping folks there culture mussels for human consumption. He told me that Lionfishes are a delicacy there and offered to "peel me one". No thanks, but I have eaten the related California 'Sculpin', Scorpaena guttata which is actually a Rockfish (aren't common names exciting?)(subfamily Scorpaeninae) cooked and sashimi and it is delicious.

Lionfishes are decidedly dangerous to handle, alive or not. I speak from painful direct and second-hand experience, having been stung myself a few times and been present when other's have been. Some people have been stuck when not exhibiting care while netting, moving a lion, dead or alive. Statistically though, more folks get poked good enough while performing tank maintenance. Whether lions are truly aggressive toward humans appears to be a matter of debate amongst recent authors. It is not to me. I have been 'challenged' by head down, spine out lions while diving and as an aquarist. Whether it is out of food-response-conditioning, curiosity, territoriality reaction or what, Lionfishes will approach your arm when its in the tank. They are unpredictable. You want to have one eye on your Lion(s) and one on the task at hand anytime you're in the system.

Eleven to thirteen dorsal spines, three anal spines and two pelvic fin spines sheath a glandular complex some two-thirds their length along anterolateral grooves. Venom passes through mechanical means, unlike the pumping action of the Stonefishes, you and the lion jamming against each other. Though not as toxic as their stonefish cousins, lion stings must be taken seriously. Swelling, soreness, localized pain, respiratory and cardiac distress, and other collateral shock manifestations go with these events. Ringing your local Poison Center, and immersing the area of entry site with water as hot as you can tolerate are immediately called for.

Natural and Introduced Range: Found in tropical Pacific and Red Sea rocky reefs, ten to two hundred feet of depth.

Size: Pterois to about a foot and a half, the dwarf genera to approximately six inches total length.

Selection: General to Specific

With Lionfishes, there is a sharp line of distinction between good, clean specimens that are going to thrive and those that on the brink of doom. They should not be hiding in a corner at the top or bottom. Dittos for hard, labored or accelerated breathing, off-color or red patches and torn fin membranes.

Choice specimens are "bright", alert, interested in their environment and are keeping a watch on you. A sure beauty mark that indicates a good individual is the presence and shape of the supraorbital antennae.

Collecting Your Own:  Can be done easily if you're in the area. Lionfishes evidently consider themselves top reef dogs. Best time to net them, right out of the open water, is between sun ups and downs. During the day look in nooks and crannies for Pterois and under rock and rubble (I'm serious) for 'dwarf species'. The usual malarkey here for permits and capture and transport paraphernalia.

Environmental: Conditions 

Other than overfeeding with too much, too soon goldfish, this is the second deadly area where aquarists fail with their lions. Lionfishes, for all their apparent slow-moving, calm breathing, seemingly low metabolic lifestyles need space. Room to move, sites to hide/feel comfortable in, volume of water to provide adequate oxygen, dilution of their, at times, copious wastes. 

Habitat: 

The bigger, the better; a good 30-40 gallons per adult Pterois and half that for other species.

Chemical/Physical:  

Though lions don't appreciate fast swings in temperature, they have enormous range tolerance. I have 'found' them in forgotten tanks at wholesalers in incredibly saline water, so much they should have been floating on top.

A super-commonplace problem with 'lion tanks' is the loss of alkaline reserve with over feeding, inadequate filtration, infrequent water changes. The scenario goes like this. Owner/keeper wants to impress most anyone and gorges lionfishes at every opportunity. Water quality tanks, with pH diving dangerously below 7.6, lions go into hiding, breathing heavily. Owner calls service company complaining. Service personnel either 1) get there quick, make massive water change and/or add buffering agent to system, or 2) get there too late with tank turning to bouillabaisse. Lesson to be learned here: keep guard on at least pH, do frequent large % water changes.

Filtration: 

Needs be capable of handling occasional large amounts of solid waste and efficient to keep ammonia and nitrites low. In the ancient days of marine aquarium keeping some writers advocated using lions instead of damsels for establishing nutrient cycling.

Display:

Provide open and closed spaces, such as lions utilize in the wild. They hide during brightest day; yours will too. Which leads us to, tah-dah, lighting. Make it subdued, low illumination flourescents, at least a dark corner. Glaring lights are implicated in lion "blindness" environmental disease.

Behavior:

Territoriality:

None toward other livestock generally. Very willing to share living space with their own and other lionfish species. Known to cooperate in feeding/herding behavior in the wild. 

Introduction/Acclimation 

Very simple. Can be first fishes. Adjust for temperature and release. 

Predator/Prey Relations:

Very easygoing with anything they can't inhale; but they do have very large, distensible mouths. Damsels, etc., and non-attached invertebrates are all so much aqua-popcorn, and should be anticipated to be ultimately sucked in. The typical 'wise-guys', triggers, puffers, large angels... you'll have to keep an eye on these so they don't hassle your lion(s).: 

Reproduction, Sexual Differentiation/Growing Your Own:

There are a few accounts (German and other mid-European) of captive, as in public aquaria, spawnings. Some scorpaenids are known to be ovoviviparous, a form of live-bearing, but Pterois are surface egg scatterers. Near artificial dusk, a male and female engage in a simple pre-spawning 'dance' culminating in upward swimming and simultaneous release of gametes while upside down beneath the surface. No record of eggs hatched and reared.

Feeding/Foods/Nutrition: Types, Frequency, Amount, Wastes

Quick! What's the number one cause of death of captive Lionfishes? Here's a little clue; what section are you reading? Foods and feeding. If food is love than most lions are loved to death. Post-mortem exams we've done invariably show fatty liver degeneration (yellow, floating blobs), frequently with accessory gut impaction from, guess what? Excessive Feeder Goldfish Gobbling Syndrome.

Here's how it works: "Check it out, Uncle Al, this here Turkeyfish can swallow a dozen of these golden beauties at a throw, Oooowhee." Don't do it! To yourself, your Lion(s), or 'feeders'! Goldfish are not a good steady diet for several reasons. They're nutritionally deficient, inconvenient, expensive.... and may make your Lion(s) aggressive. And furthermore, they're unnecessary. Lionfishes can and should be trained to accept better foods. Frozen, fresh, prepared types of all kinds; silversides, krill, shrimp, crabs, crickets... avoid oily, greasy foods, including feeders. See an abstract from Bob Fenner's article here.

Notes on food training: Using a feeding stick/rod, move the offered food in front of the lion; if not accepted, remove for another day. Not to worry if your charge goes on a food strike of a few to several days. If in good health, this presents no problem, and is a useful technique for limiting growth. A new specimen that refuses dead food may need to be weaned with live first. Try guppies or a live shrimp or crab placed ahead of the lion.

Remember, the principal cause of Lion death is over-stuffing. Do Not Overfeed. Depending on livestock and food size, desired growth rate, feed once, twice or three times a week maximum. Keep them hungry.

Disease: Infectious, Parasitic, Nutritional, Genetic, Social

Lionfish acquisition, preventative treatment and introduction follows the suggested 'Brand X' path as for most marines: 1) Quarantine for two weeks, or at least 2) Run through a freshwater, and/or marine/dilute formalin bath to reduce external parasite introduction.

Fin rot due to mis, over-handling in shipment is easily cured with furan compounds in the trade. The common protozoal scourges (Amyl)Oodinium, Brooklynella and Cryptocaryon clear up easily with copper sulfate treatment, if caught/observed in time.

Shedding of skin is something you will experience with lionfishes. Related coughing, shaking et al. may accompany it. In related species this activity is thought to aid in ridding of algae growth on camouflaging skin flaps, parasites... Once again, not to worry. 

Close:

So what have you learned from all this? That it is my opinion that lionfishes make great pet-fishes so long as you 1) are aware that they're venomous and accordingly keep your distance. 2) That they're practically indestructible, except for overfeeding, particularly with 'feeder goldfish' and 3) Water quality degradation due to number 2, overcrowding and/or inadequate filtration. Good.

Bibliography/Further Reading:

Campbell, Douglas. 1984. Pterois volitans. FAMA 9/88.

Emmens, C. W. 1983. Spotlight: Lionfishes. TFH 4/83.

Fenner, Robert. 1993. An Argument Against "Feeder" Goldfish. FAMA 11/93.

Howe, Jeffrey, Gerald Crow and Jay Hebert. 1988. The strange-eyed scorpionfish, Rhinopias xenops, with comments on it's Hawaiian distribution and aquariology. FAMA 9/88.

Kendall, J.J. 1990. Further evidence of cooperative foraging by the turkeyfish, Pterois miles in the Gulf of Aqaba, Red Sea with comments on safety and first aid. Diving for Science 1990. Proceedings of the American Academy of Underwater Sciences Tenth Annual Scientific Diving Symposium, Oct. 4-7, 1990. Univ. of S. Fla., St. Petersburg. pp. 209-223.

Kizer, Kenneth W., Howard Mckinney and Paul S Averbach. 1985.Scorpaenidae envenomation: A five year poison center experience. TFH 7/85.

Mayland, Hans J. 1975. Lionfish, beautiful but dangerous. Marine Aquarist 6(2):75.

Modlin, Jon R. 1982. The Lion Tree. FAMA 3/82.

Nelson, Joseph S. 1994. Fishes of the World, 3rd ed. John wiley & Sons, the World.

Romaine, Deborah S. 1978. The Lionfish: Mr. Personality. TFH 5/78.

With the permission of Robert (Bob) Fenner webmaster of WetWebMedia (bobfenner@aol.com) ~ Photos of Pterois Volitans by George Reclos - MCH