The Gonorynchiformes includes two modern Indo-Pacific species (Chanos chanos, Gonorynchus gonorynchus) placed in monotypic families. Several fossils are assigned to the Chanidae and Gonorynchidae (Patterson, 1975, 1987), the oldest of which are early Cretaceous. There are 24 extant gonorynchiform species in the African freshwater family Kneriidae.

Characins, catfishes, electric (knife) fishes, carps and loaches comprise a well-known higher teleostean lineage named Otophysi (Ostariophysi in older literature). This clade accounts for over 25% of modern fish species (Nelson, 1994), and most of these live exclusively in freshwater.