Lionfish Classification Essay

The Indo-Pacific lionfishes Pterois volitans and P. miles (in the scorpionfish family, Scorpaenidae) were at one time not distinguished from each other, but today they are widely recognized as distinct species based on morphometric and mitochondrial DNA analyses (Hamner et al. 2007; Betancur-R. et al. 2011; Eschmeyer 2012). Both of these predatory, venomous species have achieved notoriety during the past decade as they have invaded the western Atlantic with extraordinary speed, raising major concerns about their impacts on native hard-bottom, mangrove, seagrass, and coral reef communities. These lionfishes have now been far more thoroughly studied in the western Atlantic than in their native range. In a study in the Bahamas (Green et al. 2012), lionfish abundance was found to have increased rapidly between 2004 and 2010, by which time lionfish accounted for nearly 40% of the total predator biomass in the system. This increase in lionfish abundance coincided with a rapid (over just two years) 65% decline in the biomass of the 42 Atlantic fishes recorded as lionfish prey.

The lionfish invasion has spread all along the coastal Yucatan Peninsula, including the entire Mesoamerican coral reef, and throughout the Caribbean as far as Venezuela (Valdez-Moreno et al. 2012). Lionfish were first recorded in the western Atlantic in 2000. They have been established from Miami to North Carolina (U.S.A.) since 2002, around the Greater Antilles since 2007, and around the Florida Keys and Gulf of Mexico since 2009. Lionfish were numerous around Bermuda by 2004 and established in the Bahamas by 2005. Since 2009, lionfish have extended their range to include the Caribbean coasts of Mexico and Central and South America to Venezuela. It is unclear whether they will be able to spread south of Brazil or Uruguay. Juveniles can be found as far north as Rhode Island (U.S.A.), but under current climate conditions they apparently cannot withstand winter temperatures north of North Carolina. Lionfishes are the first nonnative marine fishes to establish in the western North Atlantic and Caribbean, although at one time or another dozens of of non-native marine fishes (most from the Indo-Pacific) have been documented in the coastal waters off Florida. (Schofield 2010) The native range for P. volitans is the Indo-West Pacific: Christmas and Cocos (Keeling) Islands in the Indian Ocean and in the western Pacific from French Polynesia and the Line Islands to Australia and Japan. The native range for P. miles is in the Red Sea and Indian Ocean: East and South Africa, Madagascar, and the Mascarenes east to Indonesia; P. miles has reached the Mediterranean Sea from the Red Sea through the Suez Canal. (Eschmeyer 2012)

The establishment of lionfish in the western Atlantic is believed to be the result of accidental or intentional releases from aquaria. Genetic analyses have revealed a striking reduction in genetic diversity in introduced populations relative to their native ranges (Hamner et al. 2007; Betancur-R. et al. 2011), but this has not caused any obvious problems for these new populations, which reach densities far higher than do populations in their native range (Kulbicki et al. 2012). Mitochondrial DNA screening of western Atlantic lionfish has shown that while P. miles is restricted to the northernmost locations (Bermuda and the east coast of the United States), P. volitans is ubiquitous and much more abundant (Betancur-R. et al. 2011).  Discouragingly, modeling by Barbour et al. (2011) suggests that effective lionfish removal programs would be very difficult to implement and maintain.

The venom-packing spines of lionfish pose a danger to anyone handling them.

Albins and Lyons (2012) reported a previously undescribed technique used by P. volitans to capture fish prey. While slowly approaching prey, lionfish produce jets of water directed toward their prey. These jets may confuse or distract prey and often result in prey fish facing the attacking lionfish, increasing the probability of head-first capture and swallowing.

Morris et al. (2009) provided an overview of the biology and ecology of P. volitans and P. miles.


Common Names:lionfish, zebrafish, firefish, turkeyfish, red lionfish, butterfly cod, ornate butterfly-cod, peacock lionfish, red firefish, scorpion volitans, devil firefish

Scientific Name:Pterois volitans (red lionfish) and Pterois miles (devil firefish)

Identification: Lionfish have distinctive brown or maroon, and white stripes or bands covering the head and body. They have fleshy tentacles above their eyes and below the mouth; fan-like pectoral fins; long, separated dorsal spines; 13 dorsal spines; 10-11 dorsal soft rays; 3 anal spines; and 6-7 anal soft rays. An adult lionfish can grow as large as 18 inches, while juveniles may be as small as 1 inch or less. Lionfish have cycloid scales (fish scales that are oval or elliptical in shape with a smooth edge).

Native Range: The South Pacific and Indian Oceans (i.e., the Indo-Pacific region). The range of the lionfish covers a very large area from western Australia and Malaysia east to French Polynesia and the United Kingdom's Pitcairn Islands, north to southern Japan and southern Korea and south to Lord Howe Island off the east coast of Australia and the Kermadec Islands of New Zealand. In between, the species is found throughout Micronesia.

Non-native Range: Lionfish have been reported along the southeastern United States coast from Florida to North Carolina. Juvenile lionfish have been collected in waters off Long Island, New York, and Bermuda. Lionfish are a popular marine ornamental fish and were possibly intentionally released into the Atlantic. The first lionfish was reported in South Florida waters in 1985 with many additional sightings occurring until they were documented as established in the early 2000s.

Habitat: Lionfish are found in mostly all marine habitat types found in warm marine waters of the tropics. Lionfish have been found in water depths from 1 to 300 feet on hard bottom, mangrove, seagrass, coral, and artificial reefs (like shipwrecks).

Ecological Role: Lionfish are slow-moving and conspicuous, so they must rely on their unusual coloration and fins to discourage would-be predators from eating them. Lionfish are now one of the top predators in many coral reef environments of the Atlantic. Lionfish consume over 50 species of fish including some economically and ecologically important species. Lionfish are active hunters who ambush their prey by using their outstretched, fan-like pectoral fins to slowly pursue and "corner" them.

Behavior: Lionfish are thought to be nocturnal hunters, but they have been found with full stomachs during the day in the Atlantic. They move about by slowly undulating the soft rays of the dorsal and anal fins. During the day, they sometimes retreat to ledges and crevices among the rocks and corals. Although in the Atlantic, lionfish are often seen moving about during the day, both alone and in small groups.

Economic Importance: Although lionfish have been used as a food source in their native range, economically, they are far more important in the aquarium trade. Lionfish are very popular and common aquarium fish, especially in the U.S.

Conservation Status: Lionfish are not currently listed as threatened or endangered in their native range. However, the increase in pollution in coral reefs may negatively affect the lionfish's primary food sources (crustaceans and fish). If lionfish are unable to adapt to declines in their prey species, their numbers may decrease.

Special Precautions: The spines of this species deliver a venomous sting that can last for days and cause extreme pain, sweating, respiratory distress, and even paralysis. Lionfish venom glands are located within two grooves of the spine. The venom is a combination of protein, a neuromuscular toxin and a neurotransmitter called acetylcholine (pronunciation: ah-see-toe-coe'-lean). After the spine punctures the skin, the venom enters the wound when exposed to the venom glands within the grooves of the spine. If you are stung by a lionfish, seek medical attention immediately.

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Biological Classification

  • Kingdom – Animalia (all the animals)
  • Phylum – Chordata (animals with a spinal cord)
  • Subphylum – Vertebrata (animals with backbones)
  • Class – Actinopterygii (ray-finned fishes)
  • Order – Scorpaeniformes (scorpion fishes and sculpins)
  • Family – Scorpaenidae (firefishes, goblinfishes, rockfishes, and scorpionfishes)
  • GenusPterois (lionfishes, turkeyfishes, and zebrafishes)
  • Speciesvolitans (meaning volatile or poisonous)

Last updated: 11/20/17
Author: NOAA
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