lionfish, (Pterois), any of several species of showy Indo-Pacific fishes of the scorpion fish family, Scorpaenidae (order Scorpaeniformes). Lionfish are noted for their venomous fin spines, which are capable of producing painful, though rarely fatal, puncture wounds. The fishes have enlarged pectoral fins and elongated dorsal fin spines, and each species bears a particular pattern of bold, zebralike stripes. When disturbed, the fish spread and display their fins and, if further pressed, will present and attack with the dorsal spines.
One of the best-known species is the red lionfish (Pterois volitans), an impressive fish sometimes kept by fish fanciers. It is striped with red, brown, and white and grows to about 30 cm (12 inches) long. The red lionfish is native to South Pacific reef ecosystems.
In the early 21st century the red lionfish became established in reef ecosystems along the Eastern Seaboard of the United States, in the Gulf of Mexico, and in the Caribbean Sea. Its rapid rate of reproduction, combined with the absence of natural enemies in those regions, resulted in its decimation of local reef fishes and its designation as an invasive species. Wildlife managers suspect that lionfish were deliberately released by pet owners into the ocean along Florida’s Atlantic coast starting in the 1980s, but damage to pet stores caused by Hurricane Andrew in 1992 may have also allowed others to escape.
These western Atlantic habitats were also invaded by another lionfish species, Miles’ firefish (P. miles; also called the devil firefish). Miles’ firefish is native to the Indian Ocean, the Red Sea, and the Persian Gulf, but by 2016 it had also established at least one breeding population along the southern coast of Cyprus. Scientists suspect that the species entered the Mediterranean basin through the Suez Canal.
Several smaller Indo-Pacific scorpaenids of the genus Dendrochirus, such as the greenish to pinkish D. barberi of Hawaii and the reddish D. zebra of the Indian and Pacific oceans, are also considered lionfish by some sources.