Marine hatchetfish facts for kids

Quick facts for kids Marine hatchetfishes
Half-naked hatchetfish, Argyropelecus hemigymnus eating a shrimp
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Stomiiformes
Family:	Sternoptychidae
Subfamily:	Sternoptychinae
Diversity
3 genera, some 40 species

Marine hatchetfishes or deep-sea hatchetfishes are small deep-sea fish. They live in the Atlantic, Pacific and Indian Oceans.

The size of marine hatchetfishes ranges from Polyipnus danae at 2.8 cm (1.1 in) to the c.12 cm (4.7 in)-long giant hatchetfish (Argyropelecus gigas).

They typically occur at a few hundred meters below the surface, but they can go up to 1,500 meters deep.

Descriotion

The body is usually silver in color, deep and extremely compressed, resembling a hatchet. The mouth is located at the tip of the snout and directed almost straight downwards. They have large, tubular eyes that are pointing upwards. That enables the hatchetfish to see the prey coming from above.

Diet

Deep sea hatchetfish feeds on plankton, crustaceans and tiny fish. They swim toward the surface of the water to look for food. They usually feed during the night and easily detect prey with their light-sensitive eyes.

Interesting facts

• Deep sea hatchetfish can produce light with their bodies. Light is produced via chemical reaction in cells that are known as photophores. These cells are located along the fish body. Hatchetfish can produce light that will have the same intensity like the faint light that is coming from above. This ability helps the hatchetfish avoid predators lurking in the depth as they become virtually invisible.

• The hatchetfish is able to jump out of the water. During the jump it can catch small insects.

• Their lifespan is less than a year.

Genera

There are three genera in this subfamily, with some 40 species altogether:

• Argyropelecus – silver hatchetfishes (7 species)
• Polyipnus (32 species)
• Sternoptyx (4 species)