The hatchetfish has upward-oriented eyes that allow it to gauge the position of prey above it. Also Their Light-producing photophores are used in a defensive behavior called counter-lighting.
The deep sea hatchetfish gets its name from the distinct hatchet-like shape of its body. It is a member of the Sternoptychidae family of deep sea fishes.
Therefore about 45 individual species vary in size from one to six inches. They are most well known for their extremely thin bodies which really do resemble the blade of a hatchet.
Also this giant of the family grows to an impressive six inches (12 centimeters) in length. Most of the smaller species are covered in delicate silvery scales.
Some species, including the giant hatchetfish can be brown or dark green in color.