Butterfishes and Relatives: Stromateoidei

Butterfishes and their relatives have large eyes, a small mouth, a forked tail fin, and a long dorsal fin. Between the gills and the esophagus, most of these fishes have a sac used for breaking down food. The inside of the sac is coated with tiny teeth. The body of butterfishes and their relatives is tapered at the ends and is either narrow from side to side or rounded in cross-section. These fishes reach a length of about 4 feet (1.2 meters). The scales usually are smooth. The color of adults varies from silver to dark brown, but young butterfishes usually have mottled colors. The dorsal and anal fins have spines. The pelvic fins are absent in some species, small in others, and large in others. The dorsal (DOOR-suhl) fin is the one along the midline of the back. The anal (AY-nuhl) fin is the one along the midline of the belly. The pelvic fins correspond to the rear legs of four-footed animals.