Pterois volitans


The marine aquarium hobby and service business would definitely be poorer were it not for the lionfishes. They are the archetypal 'stock' captive fishes. Hardy, readily available, second only to damsels in accepting disastrous water conditions. Able to be trained to accept almost all types of foods and amongst the most disease resistant of specimens, lions are, would seem to be the best of captive aquatic life; and they are.

Except for the very real probability of getting stung by their venom bearing fins by being careless, the only downside of lionfish keeping lies in picking out healthy individuals and not overfeeding them.

The Various Lionfish and Related Groups

Lionfishes are members of the scorpion- or rockfish family Scorpaenidae ("Score-pea-nah-dee") a group of fishes important to humans as food fishes and sources of envenomation (the subfamilies Synanceinae, the stonefishes, and Pteroinae, the lionfishes, among others). The non-toxic, but still very spiny rockfishes, in the genera Sebastes, and Sebastolobus are prominent table fare, sold as 'Pacific Snapper' in the U.S. though they are not in the snapper family, Lutjanidae. As Billy Shakespeare might say (or write) what's in a name; sheesh.

For those few of us into higher taxonomy, you're referred to Nelson's latest edition of Fishes of the World, 1994. Scorpaenids are part of the Order Scorpaeniformes, the 'Mail-Cheeked Fishes', referring to the numerous processes on these fishes gill covers. A brief synopsis here for sake of granting you insights into the breadth of this group, and logical links to pages on the WWM site:

Order Scorpaeniformes, the "Mail-Cheeked Fishes", 25 families, about 166 genera, 1,271 species.

Suborder Dactylopteroidei, Family Dactylopteridae, the Flying Gurnards. Two genera, about 7 species.

Suborder Scorpaenoidei. Contains world's most venomous fishes. Seven families, about 96 genera, 544 species.

Family Scorpaenidae, the Scorpionfishes and Rockfishes. 56 plus genera and 388 species.

Subfamily Sebastinae, the Rockfishes. Important foodfishes. Four genera, about 128 species.

Subfamily Scorpaeninae, various Scorpionfishes. 15 plus genera with more than 150 species.

Subfamily Sebastolobinae. Three genera of five species.

Subfamily Plectrogeninae. One genus, two species.

Subfamily Pteroinae. The Lionfishes and Turkeyfishes discussed here

Subfamily Setarchinae. Three genera, five species.

Subfamily Neosebastinae. Two genera, twelve species.

Subfamily Apistinae. Three monotypic genera.

Subfamily Tetraroginae, Sailback Scorpionfishes or Wasp Fishes. 11 plus genera and 35 species.

Subfamily Minoinae. One genus, 11 species.

Subfamily Choridactylinae (Inimicinae). Two genera, ten species.

Subfamily Synanceinae, the Stonefishes proper. Six genera, ten species.

Family Caracanthidae, Orbicular Velvetfishes. One genus, four species.

Family Aploactinidae, the Velvetfishes. Approximately 17 genera and 37 species.

Family Pataecidae, Australian Prowfishes. Three genera and nine species.

Family Gnathacanthidae, the Red Velvetfish. One species.

Family Congiopodidae, the (bizarre) Racehorses, aka Pigfishes, Horsefishes. Four genera, 9 species.

Family Triglidae, the Searobins or Gurnards. Divided into two subfamilies and three Tribes. 

Suborder Platycephaloidei, Crocodilefishes, Flatheads. Three families, 23 genera, about 75 species.

Family Bembridae, the Deepwater Flatheads. Four genera, five species.

Family Platycephalidae, Crocodilefishes or Flatheads. 18 genera of about 60 species.

Family Hoplichthyidae, the Ghost Flatheads. One genus, ten species

And more I/we'll eventually list and go over like the sculpins/cottids, agonids/poachers, hexagrammids/greenlings... but not today.

Back to the Family At Hand: Scorpaenidae:

The family Scorpaenidae's widespread importance is reflected in it's many colorful common names: Upside-Down Flying Cod, Butterfly Cod, Turkeyfish, Firefish, Scorpionfish, Zebrafish, Stonefish, Rockfish, among many others.

And The subfamily Pteroinae, Aquarium Lionfishes: 5 Genera, 17 Species

For our purposes here let's limit the discussion to the Lionfish species important to the pet fish hobby and industry; those of the genera Pterois, Dendrochirus, and Brachypterois. The first genus Pterois (Tare-oh-ease) are considered the "true" full-size lions, with huge pectoral fins, featuring unbranched rays with degrees of connecting membranes extending beyond the body at their insertion. 

The other two genera are more often sold as 'dwarf' lions. They display smaller, branched-ray pectoral fins with the rays sporting almost continuous membranes.

A brief mention here regarding 'other Lion' species. There are several other genera in the scorpaenid family offered from time to time as Lionfishes. For the most part these miscellaneous fishes are not as desirable as the species we will go over here. They are more secretive and far less appealing physically and color and pattern-wise. But, they probably are all venomous. Much more about this later, but it bears re, re, repeating: all Lionfishes are venomous and amazingly easy to get 'stuck' by. Yes, it's painful and may be very dangerous, especially is you have allergic reactions to proteinaceous stings (Stung, interested? See Wound Management for Aquarists).

And as regards the 'Freshwater Lionfish' sold in the trade; these are actually Sculpins, family Cottidae, related not too distantly to scorpaenids (in the same Order). For the record, besides not being Lionfishes, they are not venomous, or freshwater. There are some sort-of brackish water Scorpaeniform fishes, like the Bullroats, that do make forays into freshwater, but they are not permanent residents.

The Lionfishes You'll Likely Encounter Include:

  Pterois volitans (Lionfish)  

Pterois antennata (Bloch 1787), the Antennata Lion or Broad-Banded Firefish to science. This is the third lion confused with the volitans and luna species. You won't make this mistake. Antennata lions have strikingly different pectoral fin rays. These are long, the thickness of pencil lead and bright white. Also, remember the connection, between the name Antennata for it's relation to the black and white antennae (supraorbital flaps) and the six prominent spots on their face. To eight inches long.

Pterois lunulata Temminck & Schlegel 1843 , the Luna Lion, is too often mis-offered in stores as 'red volitans'. Luna lions lack the beautiful head flaps on the supraorbital bones, and have more rounded, less angular heads than volitans lions. Look closely at the two; most luna pectoral rays are connected by a web of tissue about two-thirds of their length; volitans almost totally lack this webbing. P. lunulata are typically rusty red-brown against a creamy background; occasionally specimens are offered that bear gorgeous bluish-green color at the tips of their unpaired fins. Indo-Pacific


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Pterois miles (Bennett 1828), the Devil Firefish. Indian Ocean and Red Sea. To fourteen inches in length. An occasional import from the Red Sea, though so similar to the Volitans and more expensive to transport to the west that is rarely seen in the U.S. Red Sea images. 

Pterois radiata Cuvier 1829, the Two-Bar Lion is the Radial Firefish. The most chameleonic of lions showing overtones of green, black and various shades of red over shocking white. The salient identifying characteristic of this species is the two while horizontal bars on the caudal peduncle, the part of the body right before the tail. Aquarium and Red Sea specimens. To nine inches.


Pterois sphex Jordan & Evermann 1903, the endemic Hawaiian ("Dwarf") Lion; often mistakenly sold as Antennata lions which they closely resemble in terms of pectoral finnage. Sphex lion fins are shorter, less colorful and more clubbed in appearance. Though more costly than the majority of lions which are imported from the Philippines and Indonesia, Hawaiian lions are my favorite for hardiness. To eight inches.


Pterois volitans  ("Tare-oh-ease vawl-it-tanz) (Linnaeus 1758),  is the Lionfish to most folks. It is the most commonly displayed and sold member of the family; the quintessential marine aquarium specimen, with it's long flowing pectoral and dorsal fin rays. Volitans lions span the color range of banded red to black against alternating creamy white. Yes, black and red volitans lions are the same species. These images from the Red Sea.

'Dwarf' Lionfishes in the genera Dendrochirus ("Den-droh-kear-us) and Brachypterois ("Brack-ee-tear-oys") are labeled as such for their smaller size and more sedentary, bottom-dwelling habits.

Dendrochirus biocellatus (Fowler 1928), the Twin-Spot, Roo or Fu Man Chu Lion is unmistakable with it's two eye spots on the rear dorsal fin area, and two whisker-like appendages extending from the lower jaw. To almost five inches in length. Aquarium images.


Dendrochirus brachypterus ("Brack-hip-tur-us") (Cuvier 1829), The Shortfin Dwarf Lion is a rarer, more heavy bodied dwarf, often showing up with a good deal of yellow, brown and green mixed with red markings. Brach dwarfs are aptly named in reference to their very large pectoral fins with almost no emerging ray tips. This is one of the most personable marine species, quickly getting to recognize and respond to it's owners presence.

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Dendrochirus zebra (Cuvier 1829), the Zebra Turkeyfish, is the most common dwarf lion is similar in many ways and degrees to P. antennata and P. sphex. The one sure distinguishing mark of D. zebra is the presence of two white spheres on it's caudal peduncle. To ten inches in length. Shown: an individual and "tree" of individuals in captivity.

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

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