Black seasnail, Paraliparis bathybius
Black Seasnail, Paraliparis bathybius

While most seasnails can be easily recognized by their characteristic adhesive disc, it is absent from this species. Its body shape is typical of snailfish, long and tapering, with a large head, dorsal and anal fins that run the length of the body, and a much reduced caudal fin. Its pectoral fins are unusual in that they have two lobes, the lower consisting of 3 or 4 separate rays. The mouth is horizontal with broad bands of teeth that are used to crush amphipods, snails and crustaceans. Overall, the body colour is black, fading to a dark grey towards the posterior end of the fish. Black seasnails reach a maximum length of 25 cm.

This species is found in the north Atlantic from off west Greenland to Baffin Bay in cold, deep water and individuals have been hauled up from as deep as 4000 m! Because of their deepwater habitat, not much is known about their biology except that spawning likely takes place in the summer and females produce over 400 eggs.