Half-naked hatchetfish

Taxobox
name = Half-naked hatchetfish

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image_caption =
image_wdith = 240px
regnum = Animalia
phylum = Chordata
classis = Actinopterygii
ordo = Stomiiformes
familia = Sternoptychidae
subfamilia = Sternoptychinae
genus = "Argyropelecus"
species = "A. hemigymnus"
binomial = "Argyropelecus hemigymnus"
binomial_authority = Cocco, 1829

The half-naked hatchetfish, silver hatchetfish or spurred hatchetfish, "Argyropelecus hemigymnus", is a deep-sea hatchetfish of the genus "Argyropelecus" found in deep tropical and subtropical waters of all oceans. Its length is between 3 and 5 cm.

The half-naked hatchetfish is a small deep-bodied species with a long narrow trunk ending in an extended caudal peduncle. The large eyes are directed upwards, enabling prey to be silhouetted against the faint light coming from the surface, and the large mouth is also directed upwards. Much of the belly is covered in downward directed photophores, which are thought to disguise the fish's dark shape from other upward-looking predators.

This silvery coloured plankton-eating fish migrates upwards from its 350 to 550 m daytime range to 150 to 300 m during the night, becoming lighter in colour as they do so.

References

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* Tony Ayling & Geoffrey Cox, "Collins Guide to the Sea Fishes of New Zealand", (William Collins Publishers Ltd, Auckland, New Zealand 1982) ISBN 0-00-216987-8