bony fish

Fish of the class Osteichthyes, the largest and most important class of fish. The head covering and the scales are based on bone. Bony fish have a swimbladder, which may be modified into lungs and the gills are covered by a flap, the operculum.

The bony fish are divided into two subclasses.

Subclass Sarcopterygii, the fleshy-finned fish, has two orders: Crossopterygii, represented today by the coelacanth, and Dipnoi, represented by the lungfish.

Subclass Actinopterygii, which contains all those fish whose fins are supported by bony rays, is sometimes divided into three superorders: Chondrostei, which includes the sturgeons, birchirs, and reedfishes; Holostei, which includes the garpikes and bowfins; and Teleostei, which includes about 20,000 species of ‘modern’ bony fishes, such as salmon, pike, and cod.