(Pterois), any of several species of showy Indo-Pacific fish of the scorpion fish family, Scorpaenidae (order Scorpaeniformes). Lion-fish 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 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.

Also known as fire-fish or lion-fish are 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 Orient.