The longnose lancetfish (Alepisaurus ferox) is a deep-sea fish in the family Alepisauridae, whose most striking features are an enormous sail-like dorsal fin running from its back nearly to its tail, and long, sharp fangs lining its jaws. It reaches a maximum length of about 215 cm (roughly 2.1 m) and lives in the bathypelagic to abyssopelagic zones at depths of 200–1,800 m. Widely distributed across temperate and tropical open oceans worldwide, it's frequently caught as bycatch in tuna longline fishing, earning it a reputation as "the deep-sea fish tuna fishermen dislike."