Etheostomatinae is a species-rich subfamily of freshwater ray-finned fish, the members of which are commonly known as the darters. The subfamily is part of the family Percidae which also includes the perches, ruffes and pikeperches. The family is endemic to North America. It consists of three to five different genera and well over 200 species. A common name for these fish in southern Indiana is pollywog.

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.