[3][4][5] Stomias ferox has an elongated body and small head;[6] it is up to 30 cm (0.98 ft) in length, black underneath and iridescent silver on its flanks, with a barbel that has a pale stem, dark spot at base of bulb and three blackish filaments.

In Icelandic it is marsnákur ("sea snake") and in Norwegian storkjeft ("big jaw").

[14][15] Stomias ferox is mesopelagic and bathypelagic, living at depths of 20–800 m (66–2,625 ft), concentrated in the north Atlantic.

[16][17] Stomias ferox eats midwater fishes and crustaceans; it rises to near the surface to feed at night.

[8] It positions itself horizontally in the water column with pelvic and pectoral fins spread wide and barbel pointing forward.