They should not be confused with the freshwater hatchetfishes, which are not particularly closely related Teleostei in the characiform family Gasteropelecidae.

[1] The scientific name means "Sternoptyx-subfamily", from Sternoptyx (the type genus) + the standard animal family suffix "-inae".

They are small deep-sea fishes which have evolved a peculiar body shape and like their relatives have bioluminescent photophores.

[1][5] The body is deep and laterally extremely compressed, somewhat resembling a hatchet (with the thorax being the "blade" and the caudal peduncle being the "handle").

Their large, sometimes tube-shaped eyes can collect the faintest of light and focus well on objects both close and far.