The Percidae are a family of ray-finned fish, part of the order Perciformes, which are found in fresh and brackish waters of the Northern Hemisphere. The majority are Nearctic, but there are also Palearctic species. The family contains more than 200 species in 11 genera. The perches and their relatives are in this family; well-known species include the walleye, sauger, ruffe, and three species of perch. However, small fish known as darters are also a part of this family.
The family is characterised by having the dorsal fin split into two[1] which are normally separated or have a narrow connection, although this is wider in the genus Zingel, the front section contains the spines and the rear section contains the soft rays.[1] The anal fin contains 1 or 2 spines, if there is a second spine it is typically weak. The pelvic fins are placed on the thorax and have a single spine and 5 soft rays. They also have skeletal synapomorphies. The maximum size attained is 100cm (00inches) in the zander (Sander lucioperca) but most of the species in the family are much smaller. Their scales are ctenoid and their bodies are normally somewhat elongate.[2]
The 5th Edition of Fishes of the World classifies the Percidae into five subfamilies[3] and Fishbase recognises 239 species in 11 genera.