Axefish

This is the smallest of the deep-sea hatchetfishes, a bright scrap of silver that fits on a fingertip. It lives in open water in the Atlantic, Indian and Pacific Oceans and in the Mediterranean. Most stay between 100 and 700 metres, though the species has been taken as deep as 2400 metres. Adults climb towards shallower water at night and drop again by day. They eat zooplankton, the small drifting animals of open water, taking mainly ostracods and copepods at dusk, with small fish now and then. Eggs and young float freely in the water. Nets bring them up singly or in small groups rather than in shoals.

Also known as: common hatchetfish, half-naked hatchetfish, half-naked hatchetfish, hatchet-fish, halfnaked hatchetfish, hatchet fish, heath's hatchet fish, spurred hatchetfish, silver hatchetfish, heath's hatchet fish, halfnaked hatchetfish, hatchetfish, common hatchetfish, hatchet fish, half-naked hatchetfish, half-naked hatchet-fish

Several hatchetfishes share the same mirror-sided shape, so go by size. This one is the smallest of the group and rarely gets near the length of its relatives. Do not use the night-time darkening as your mark, because that colour comes and goes.

A very deep, thin body pressed flat from side to side, so the fish looks like a small axe head. By day the body is bright silver. At night the body and trunk take on a dull, darker cast. Maximum length is 5.1 cm and maximum weight about 1.4 g.