Appearance
Found most often at depths of 200–600 meters in tropical, subtropical and temperate waters of the Atlantic, Pacific and Indian Oceans, marine hatchetfishes range in size from Polyipnus danae at 2.8 cm (1.1 in) to the c.12 cm (4.7 in)-long giant hatchetfish (Argyropelecus gigas).
The members of the disputed subfamily Maurolicinae have a more conventional fish shape. The mouth is located at the tip of the snout and directed downwards, more so in the Sternoptychinae.

