; subclass Actinopterygii, order Perciformes)
A large family of freshwater fish, including the true perch (Perca fluviatilis), 45 cm, that usually have a fairly deep and fully scaled body, with two separate dorsal fins, a slightly forked tail fin, and pelvic fins located close to the pectoral base. Several members of this northern hemisphere family have been introduced to other continents. The family includes a number of important food fish, e.g. the perch, and Stizostedion vitreum (wall-eye), 90 cm, which is one of the largest species. There are at least 126 species.
Subjects: Zoology and Animal Sciences.