Gymnocephalus

Gymnocephalus
Eurasian ruffe, (G. cernua)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Perciformes
Family:	Percidae
Subfamily:	Acerinae Bleeker, 1858[1]
Genus:	Gymnocephalus Bloch, 1793
Type species
Perca schraetser Linnaeus, 1758[2]
Synonyms[3]
Acerina Güldenstädt, 1775 (either unavailable or needs to be suppressed) Cephimnus Rafinesque, 1815 Acerina Cuvier, 1816 Cernua J. Fleming, 1828 Gremilla Gistel, 1848 Leptoperca T. N. Gill, 1861

Gymnocephalus is a genus of ray-finned fishes from the family Percidae, which includes the perches, pike-perches and darters. They are from the Western Palearctic area, although one species, Gymnocephalus cernua has been accidentally introduced to the Great Lakes region where it is regarded as an invasive species. They have the common name "ruffe" and resemble the true perches in the genus Perca, but are usually smaller and have a different pattern.