Perches, Ruffes, and Allies

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 nearly 250 species in 12 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.

Despite the widespread and speciose nature of this family, the vast majority of its species diversity is within the darters, which are restricted to eastern North America, and the majority of which have small ranges. Excluding the darters, this family contains only 20 species. In Europe, percids were likely a more ecologically dominant group in the past than now, with the immigration of cyprinids to Europe during the Miocene causing a decline in their importance.