hatchetfish

noun, plural (especially collectively) hatch·et·fish, (especially referring to two or more kinds or species) hatch·et·fish·es.

1. any deep-sea fishes of the genera Argyropelicus, Sternoptyx, and related genera, of tropical and temperate waters, having a silvery, hatchet-shaped body.
2. Also called flying characin. any of several freshwater fishes of the genera Carnegiella, Gasteropelecus, and Thorachocharax, occurring from Panama to the Rio de la Plata and capable of flying short distances by rapid movements of their large pectoral fins.