Percopsiformes

The Percopsiformes are a small order of freshwater teleost fishes measuring less than in length, comprising the trout-perch and its allies. It contains just ten extant species, grouped into seven genera and three families. Five of these genera are monotypic.

species of fish

thumb|Amphiplaga brachyptera

species of fish

Percopsis is a small genus of percopsiform fishes native to North America, with these two recognized species: Percopsis omiscomaycus (Walbaum, 1792) (trout-perch) Percopsis transmontana (C. H. Eigenmann & R. S. Eigenmann, 1892) (sand roller)

Erismatopterus is an extinct genus of percopsiform fish which lived during the early to middle Eocene epoch and containing the single species Erismatopterus levatus. A report of the genus in sediments of similar age in Washington State have been discredited. Erismatopterus is treated as part of the family Percopsidae, but formerly was the type genus of the extinct family Erismatopteridae. The genus is closely related to Amphiplaga of related lake sediments. Shoaling behavior has been reported from a mass mortality fossil of E. levatus and attributed as a predator-evasion response behavior.