It Don’t Mean a Thing if it Ain’t Got That Sting

Scorpionfish in the Home Aquarium

Greg and Renee Hix

"You put your hand in THAT tank??!!" is a common response we hear when folks find out that we keep scorpionfish. However, it's no surprise when one considers the tales of death, woe, and aggressiveness that are often associated with this mild-mannered and fascinating group of fishes. It seems unfair that scorpionfish tend to get lumped into the aggressive category simply because they will eat anything that fits into their rather large mouths, or because they are venomous. To be honest, these fish are more likely to be the victims of bullying rather than the bullies.

While the family Scopaenidae is a rather large group of fishes containing approximately 45 genera and 388 species, this article will focus mainly on species generally available to the aquarium trade, and will exclude subfamily Pteroinae (lionfishes), and the genus Rhinopias, as these will be the subjects of their own dedicated articles.

General Description and Habitat:

While the identification of species can sometimes be tricky, scorpionfish do share some common morphologicaltraits which include large heads, mouths, and eels, as well as a bonyridge running from the eye across the cheek (known as the suborbital stay). Non-venomous spines are present on the opercula and head, and of course, there are the stiff fin spines which deliver the painful punch of the scorpionfish's venom. The toxicity of this venom varies from family to family, with the stonefish being the most toxic, and in some cases, deadly.For this reason, true stonefish are rarely, if ever, found in the aquarium trade.

Another interesting trait shared by many Scorpaenids is the ability to shed their cuticle. The cuticle is actually a thin, diaphanous outer skin that protects these sedentary fish from ectoparasitic pathogens, algae growth, etc. Some species, such as Rhinopias shed their cuticles as often as two or three times a month, while others do so less frequently. Cuticle shedding can look a bit disturbing, as the fish will yawn, flare their gills, and twitch their bodies to loosen the cuticle. At some point, the fish will typically dart or dive and pieces of the cuticle will simply float off into the water column, looking like a milky ghost, and the scorp will look bright and shiny in its new cuticle. The ability to shed their cuticle is one of the chief reasons these fish are so disease resistant.

Scorpionfish are represented in virtually every ocean of the world, and while most occur on the temperate reefs, there are a number of tropical species as well. Scorps can be found living on both hard and soft substrates, often in caves, crevices or under overhangs. Many of the species found on softer substrates have high-set eyes and often burrow into the substrate to lie in wait for a passing meal. In fact, most scorpionfish blend so well with their environment, they are often overlooked by divers and aquarists alike. I have often had guests in my home peer into some of my aquariums and ask where the fish are, even if the fish are sitting "front and center"!

Let's Meet Some Scorps:

Scorpaenodes caribbaeus (Reef Scorpionfish)

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Maximum Size: 4.75" TL Natural Habitat:As its common name implies, this fish is found associated with reefs.  Distribition is the western Atlantic: Florida, USA and Bahamas to Panama and northern South America. Antilles, western and southern Caribbean. Depth: to 18 m Minimum Tank Size: 30 gallons. Rather common on the reefs, but not very common in the trade, these fish are perfect for a smaller setup.   These fish are a bit cryptic at first, and even after becoming established, are often found upside down in caves and overhangs, or stands of macro algae.  Our specimen definitely makes its presence known when it sees us in front of the tank, hoping for a tasty morsel.  This fish can be recognized by its spotted fins, as well as a mask of spots across its eyes, and a line of spots on the caudal peduncle.  Our specimen was originally white overall, with a dark diagonal band across its body, but the white background is now a nice pastel salmon color.  This fish was “medium” difficulty in terms of weaning, and is now a solid stick feeder, although it would suffer from competition.

Scorpaena brasiliensis (Red Barbfish, Barbfish, Goosehead Scorpionfish)

Maximum Size: 10"-12" TL Natural Habitat: Occurs on and around reefs in the Western Atlantic: Virginia, USA and northern Gulf of Mexico to Brazil; not occurring in Bermuda. Depth: 1 to 100 meters. Minimum Tank Size: 55 gallons. Although most scorps can be just about any color based on their habitat, this species is generally mottled shades of reds and browns with white highlights, and are quite handsome fish. S. brasiliensis is probably the most common scorpionfish available to the hobbyist, and certainly one of the easiest to care for. It is very hardy and easily fed, as most specimens accept dead food readily, both from a feeding stick or the water column. Although many scorpionfish are cryptic or simply sit there looking like a rock, this species is quite personable and will soon recognize its keeper, looking for a handout.

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Scorpaenodes littoralis (Cheekspot Scorpionfish)

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Maximum Size: 4.5" TL Natural Habitat: Occurs in association with reefs, drop-offs, and rocky caves. Its distribution is somewhat scattered in the Indo-West Pacific and off the Eastern coast of Africa. Depth: 2 - 30 m Minimum Tank Size: 30 gallons. A very pretty fish,they are typically mottled shades of red, with a dark cheekspot at the lower edge of the opercula as well as light bars on its lips and chin. Our specimen is shades of red with pink markings. This fish is fond of caves and overhangs, and you will often find it upside down on the ceilings of these areas as well as upside down in lush growths of macro algae. They are bold, yet can be a bit cryptic until they get adjusted. This is one of the quickest scorps we keep, and our specimen zips out and strikes its food almost before you realize it is coming.

Sebastapistes strongia (Barchin Scorpionfish)

Maximum Size: 3" TL Natural Habitat: Occurs in areas with mixed sand and rubble in reef flats, shallow lagoons and channels. Its distribution is the Indo-Pacific, the Red Sea, and East Africa to the Society Islands, north to Taiwan, south to Queensland, Australia. Depth: to about 18 meters. Minimum Tank Size: 20 gallons. A nocturnal fish, this little scorp is a bit more reclusive, preferring to lie partially buried in the substrate during the day, becoming more active under dim lighting. Its natural diet is small fish and shrimp, and these should be offered at first, although this fish also tends to train fairly well to frozen fare. Their small size makes them perfect for the aggressive smaller aquarium, and there should be a suitable substrate (no larger than #3 grade aragonite) and a few pieces of rubble rock to hide amongst in open areas of the aquarium. This species is not very common in the aquarium trade, but is occasionally available.

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Sebastapistes cyanostigma (Yellow-Spotted Scorpionfish)

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Maximum Size: 3" TL Natural Habitat: Occurs on reefs with rich SPS growth, as this species typically inhabits the branches of Pocillopora, Millepora, and Styllophora coral heads. Its range is the Indo-Pacific: Red Sea south to Port Alfred, South Africa and east to the Line Islands, north to Ryukyu Islands, south to Samoa and Australia. Depth: to about 30 meters. Minimum Tank Size: 20 gallons. These are certainly one of the gems in terms of appearance, sporting a red to deep pink body and bright yellow spots. Unfortunately, it can also be a bit on the reclusive side, often preferring to take up residence in live SPS colonies or SPS skeletons, although they may also feel comfortable with a rubble-strewn substrate. Our specimen is not overly shy, and took readily to stick feeding. These diminuative scorps are best started on live ghost shrimp to get them to feed initially (it would not take guppies unless they swam down in front of it). Not super common, but well worth keeping if you can find one.

Taenianotus triacanthus(Leaf Scorpionfish, Leaffish, Sailfin Leaffish, Paperfish)

Maximum Size: 4" TL Natural Habitat: Inhabits reef flats, outer reef slopes, current-swept channels, and is occasionally found on lagoon reefs.  Distribution is the Indo-Pacific: East Africa to the Galapagos Islands, north to Ryukyu and Hawaiian Islands, south to Australia and the Tuamoto Islands. Depth: to about 30 meters. Minimum Tank Size: 10 gallons for one or two specimens, 20 gallons for up to a trio. These little fish are quite comical in their behavior. Being true to their name, they mimic dead leaves swaying in the current, but the fun doesn't end there. Rather than swim, these cute little scorps move from place to place by crutching or hopping along the substrate. In fact, they soon recognize their keepers, and will come hopping over to beg for a handout. Their bodies are extremely laterally compressed, with a high, sail-shaped dorsal fin. They come in a variety of colors, yellow, brown, red, or mottled. The deep red specimens are striking, but unfortunately, almost always fade to a pinkish cream color in captivity. Roll over the picture to the right of the red leaf to see how they can change colour quickly when introduced to your tank. They do well in pairs and trios, and can make for a nice little display. About the only thing I can say that some consider negative is the fact that they can be difficult to wean onto dead food items, so be prepared to offer gut-loaded ghost shrimp for the life of the fish. That being said, these fish do seem to be easily trained to take food from a small net. How many fish have you seen hurry INTO a net?

Additional Photos Move the mouse over the picture to see how a bright red specimen turned a pale color after a time in captivity.

Pteroidichtys amboinensis  (Ambon Scorpionfish, Ambon Lionfish)

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Maximum Size: 4" - 5" TL Natural Habitat: Occurs on reef flats and lagoons, typically found within clumps of algae. Its range is the Indo-West Pacific: known from disjunct localities. Red Sea, Indonesia, Papua New Guinea, Japan, and Saipan known only from five specimens taken from the Ryukyu Islands, Celebes, Ambon, Viet Nam, and Madras. Depth: unknown, but probably to about 20 meters. Minimum Tank Size: 10 gallons for one or two specimens, 20 gallons for up to a trio. A rare gem, indeed, but fabulous little fish. Their appearance can be variable, depending on their habitat. Some appear shaggy, with almost hairlike dermal appendages covering their bodies, while others are almost smooth. Some have antler-like supraorbital appendages that remind you of reindeer, while others do not. This fish is actually very similar in shape to fish from genus Rhinopias, but in a smaller package. They are mild-mannered and entertaining fish that will soon know who the "food god" is and will come crutching over on their lacy pectorals, ready for a meal. On the subject of food, these fish do not wean easily to frozen, and may need to be offered live ghost shrimp and guppies for life. Unfortunately, for whatever reason, these fish typically don't survive long in captivity, and a specimen that seems to be thriving and is eating well will often simply be found dead after a few months. Hopefully, someday, whatever is missing in their care will be understood, and they will become easier to keep.

Please Don’t Feed Me Goldfish!:

Now that we have your attention, let's discuss feeding your scorps. First of all, let's talk about live feeder fish. The flesh of freshwater fish, does not contain the proper fatty acids required to keep saltwater predators healthy. This is especially true of members of the carp family, such as goldfish and rosy reds. Another big problem is that these fish also contain the enzyme Thiaminase, which inhibits the uptake of Thiamine. An extended diet of freshwater feeders usually results in poor growth rate, disorders of the nervous system, clamped fins, cessation of feeding, and you guessed it, an early death.

Another food to avoid is krill, frozen or freeze-dried. Krill has been linked to lockjaw in many predatory species, and although it is typically well-received by most fish, it is not recommended. In fact, some people in the hobby refer to freeze-dried krill as "fish crack" since some fish will decide they will only eat this food and nothing else once it has been offered a few times.

About now is where you might be wondering "OK, smart guy, just what DO I feed my fish?", so let's find out:

Live Foods:

While we don't recommend a steady diet of live food, it may be necessary to feed new specimens live fare initially to get them eating, or in some cases, where certain fish are difficult, or simply refuse to be weaned onto dead foods, this may be their diet for life.

Ghost or grass shrimp (fresh or saltwater) are both excellent foods, especially since they can be enriched ("gutloaded") with nutritious things like high quality flake food, spirulina, beta glucan, etc.

Fresh/frozen foods:

Silversides are an excellent food since they are easily stuffed with pelletized food, powders (such as spirulina orbeta glucan), etc. One can also find many other frozen foods in the freezer at the local fish store (LFS), however, we find that a wider variety of fresher, high quality seafood is available at the grocery store or local fish market.

For a detailed article regarding weaning techniques, be sure to read our "Tools of the Trade" guide: LionfishLair Feeding Techniques.

Feeding Frequency:

Due to their sedentary nature and slow metablolism, adult scorpionfish should only be fed twice or three times a week. Feed them until you see a slight bulge in their bellies, once you see this, you will understand my meaning.
We do, however, feed our juvenile specimens a bit more often since much of their caloric intake is used for growing. A good feeding schedule for us has been to feed the adults Monday-Wednesday-Friday. Our juvies typically get a bit of food each day between normal feedings.

Given the chance, many scorps will overeat, sometimes to the point of regurgitation, which obviously, should not be encouraged. You will get a feel for how many food items of appropriate size makes up a meal for your fish.

Overfeeding your fish on a long term basis will likely shorten its life due to fatty liver degeneration. Additionally, owing to these fishs' slow metabolism, large food items can sometimes begin to decompose in a scorpionfish'sdigestive tract before they can be digested, resulting in bloating and death.Don't worry if this paragraph seems scary, it's simply helpful to know.

Housing your Scorp:

Due to their sedentary nature, scorpionfish can be kept in tanks from 10 gallons on up, depending on species. While it is always best to research the aquascaping requirements of a given species, a tank with a good amount of surface area rather than height is a good choice, such as long or wide tanks. A sand substrate is best, as many species will partially bury themselves on occasion.I have had good success with #1 or #3 grade aragonite. Live rock caves and overhangs are appreciated by many species, as well as stands of macroalgae, which also aid in water quality via nutrient export. A bit of rubble here and there on the substrate will complete the setting.

Biofiltration should be robust, no matter what type of equipment you use, as scorps tend to produce a good amount of waste. Also, many of the foods they eat are a bit oily, so we recommend a good skimmer. Sump-based systems will boost water volume, and are my favorite option. Again, lots of live rock and macroalgae are your friends.

Generally speaking, scorpionfish are not very fussy about their lighting requirements. For the most part, they are crepuscular (dawn/dusk) predators, so their lighting can be simple normal output (NO) fluorescents, however, they are just as happy under brighter lighting, provided there are some dimmer areas to retreat to. So, the rule of thumb is to light their tank with lighting suitable for their tankmates. Whatever type of lighting you use, a dawn/dusk photoperiod using actinic and daylight lamps would be a perfect lighting scheme.

Many scorps are excellent reef candidates, as they have no interest in coral, and will not harm them. Frank Marini, noted scorpionfish afficionado, has coined the phrase that scorps are "reef limiting" in that they will indeed limit your stocking options a bit. Scorps will eat ornamental shrimp, crabs, and any fish that will fit into their often cavernous mouths. Besides being too large to swallow, piscine tankmates should not include browsing fish that normally pick at rocks (e.g., tangs, angelfish, and many wrasses), or known fin nippers (most triggers, puffers, etc.).

”The Big Question”…What Do I Do If I’m Stung?

You've probably been wondering this in the back of your mind ever since you decided to read this article, haven't you?  We could go into the mechanics of how the venom is injected, however, this is really more of a scorpionfish primer, and we’d hate to have you nodding off.  That being said, the absolute best advice we can offer is “DON’T GET STUNG!”  However, accidents do happen, and what can we say?  It's going to hurt... just how much depends on which species you take the hit from, its size, how much venom is injected, and the time the spine is embedded in your skin.

First aid for a scorpionfish sting is immersion of the affected area in hot water (114°F) for 20 up to 90 minutes, or until the pain subsides, in order to inactivate the thermolabile components of the venom. The reason for applying heat to the wound is because some scorpionfish venom is composed of heat labile proteins, and the heat actually denatures the venom. Please, don't use scalding-hot water, as the resulting burn will likely do more damage than the venom. To ensure the proper temperature have a cooking thermometer on hand.

Don't worry, unless you happen to be allergic to the venom, or you get stung by a stonefish, your life really isn't in danger from the effects of the venom. That being said, you need to guard against secondary infection of the wound as well as make certain that there are no pieces of the spine left in the wound, which can cause infection. A tetanus booster is recommended if it is past due. To that end, you may want to seek professional medical assistance, just in case.

Fortunately, in over 20 years of keeping venomous fish, neither of us has never been stung (knock on wood), so we can’t tell you what it feels like. However, we're not in a hurry to find out, as we're told it really hurts.  One thing that may make lions a bit more dangerous than other scorpionfish in terms of getting poked is the fact that they are very inquisitive, and some of the bolder specimens that become very accustomed to you will swim around the exact spot you’re working in. Tapping these fish lightly on their tails can teach them to mean go to a neutral corner, and they will typically stay thee. Could this backfire on us someday? You betcha, however, here are some tips for working in the lion’s den:

1. Always respect the fish, and know where they are at all times when working on the tank. If you happen to be performing a chore that requires a lot of your concentration, you may want to enlist the aid of a spotter to let you know if the fish is nearby (this is a perfect job for young helpers).
2. Never make the fish feel threatened or cornered. Perform your work deliberately and in a non-threatening manner. Get to know your fish, and let it get to know you. Scorpionfish are pretty intelligent and will become accustomed to you working in their box of water.
3. Know the warning signs that a scorpion has gone into a defensive posture.  They will typically erect their dorsal spines and assume a head-down position, thus bringing their daggers to bear in the direction of the perceived threat.

4. Don’t pet the fish! This was actually meant as a joke, but I know of at least one case, where a person thought her lionfish was so puppy-like and tame that she tried to pet it and got poked for her trouble.  She was unaware of the first aid for a sting, applied ice to the wound, and ended up in the ER.

Wrapping it up:

Although marine aquarists have been keeping scorpionfish and their kin for quite awhile, it is our hope that this article has piqued your interest in them. They are interactive, peaceful, hardy and disease-resistant fish, each with their own distinct personality, and they are certainly one of the most off-beat and unique group of fish you are likely to encounter. It has been a pleasure sharing our passion for them, and giving you a window to their care and habits, as well as other useful information and tips based on practical experience for keeping them successfully. Happy scorp-keeping, and remember: "It don't mean a thing if it ain't got that sting!

Bibliography:

Auerbach PS. Marine Envenomations. N Eng J Med. 1991; 325:486-493.

Kizer KW. McKinney HE, Auerbach PS. Scorpaenidae Envenomation: A Five-Year Poison
Center Experience. JAMA 1985; 253: 807-810.

Marini, Frank C., Ph.D. 2010.  Lionfishes and Other Scorpionfishes

Michael, Scott W. 1998.  Reef Fishes, Vol. 1 (pp. 453-489)

Vetrano, SJ, Lebowitz, JB, Marcus, S., Lionfish Envenomation. Journal of Emercencey Medicine. 2002, Nov 23(4): 379-82

Online Sources:
Fish Base  http://www.fishbase.org

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

Fatheree, James W., M.Sc.  Lionfish Envenomations and the Aquarist

Gallagher, Scott A., MD, FACEF; Adler, Jonathon, MD. Lionfish and Scorpionfish. 2011, May12.