- any of several marine fishes of the families Trachipteridae, Regalicidae, and Lophotidae, having a long, compressed, ribbonlike body.
- any of several related fishes, as the oarfish.
- any of several unrelated but similar fishes, as the cutlassfish and jackknife-fish.
- any of various soft-finned deep-sea teleost fishes, esp Regalecus glesne (see oarfish), that have an elongated compressed body. They are related to the opah and dealfishes
