Basses Perches and Relatives: Perciformes

When people close their eyes and picture a fish, they probably see a member of Perciformes (puhr-sih-FOR-mehs), the largest order not only of fishes but also of invertebrates (in-VER-teh-brehts), or animals without backbones. There are about seven thousand species in the order Perciformes. Fishes in Perciformes vary from tiny gobies and darters to huge marlins and swordfishes. The body shape varies from long and thin like that of wolf-eels to short and round like that of yellow tangs. Most fish in this order, however, are the familiar "fish" shape of perch, bass, tuna, and bluegill.

The traits that most fishes in Perciformes have in common are spines on the front parts of the dorsal and anal fins; pelvic fins made up of one spine and five rays, or supporting rods; rough scales; and the presence of a lateral line. The dorsal (DOOR-suhl) fin is along the midline of the back, and the anal (AY-nuhl) fin is along the midline of the belly. The pelvic fins correspond to the rear legs of four-footed animals. The lateral (LAT-uhr-uhl) line is a series of pores and tiny tubes along each side of a fish's body and is used for sensing vibrations.