Boa dragonfish, Stomias boa.

Boa Dragonfish, Stomias boa

This fearsome looking fish is distinguished from its close relative, the shortbarbel dragonfish, by six rows of hexagons that are formed by the scales along the sides of its body. They are located above the photophores, of which there are 89–91 running lengthwise down the body. As well, the chin barbel, which is as long as the head, has three short filaments on a bulb at the end. Its dorsal fin is very short and close to the caudal fin. The anal fin mirrors the dorsal fin in size, shape, and placement, while the caudal fin is short and extremely rounded. The pelvic fins are long and placed very close to the posterior end of the fish, while the pectoral fins are much reduced. The head is large in comparison with the body, and the mouth has a set of nasty looking teeth that are used to hold struggling prey before they are swallowed. A boa dragonfish body is iridescent silver on its sides; its back and belly are black.

The boa dragonfish occurs in the North Atlantic, Pacific, and the Canadian parts of the Arctic Ocean, but little is known about its biology due to its preferebce for deep water habitats. However, a number of individuals have been caught at 300 m and one Canadian specimen was recovered from the stomach of a swordfish caught off the coast of Newfoundland.