Lancet fish

The short-snouted lancetfish is a long, thin hunter of the deep open ocean. It reaches about 96 cm, with most fish nearer 70 cm, and carries a huge sail on its back. Its body is soft and watery, so it cannot chase prey for long. Instead it hangs still in the dark water and strikes.

Also known as: shortnose lancetfish, shortsnout lancetfish, lancetfish, shortsnouted handsawfish, shortsnouted lancetfish, short snouted lancetfish, shortnose lancetfish, shortsnout lancetfish, shortsnouted handsawfish

The fish to rule out is the long-snouted lancetfish, which shares the sail, the fangs and the scaleless body. The snout is the only thing that separates them. On this species it is shorter and blunter, while on the other it draws out long and pointed.

The body is slim and flattened from side to side. It is deepest at the gill covers and narrows to a thin stalk before the tail. A tall rounded dorsal fin runs along most of the back, standing about twice as high as the body is deep, and it folds down into a groove. A small fleshy adipose fin sits behind it. The mouth is wide and opens back past the eye, with two or three large fangs in each jaw among many smaller teeth. The tail is deeply forked and the upper lobe draws out into a long thread. The colour is an iridescent brown-black above and paler below, with a line of white spots along the dorsal fin. There are no scales at all, and the fins tear easily.

This is an open-water fish of the deep sea, far from any bottom. It lives in the tropical and subtropical Atlantic and in the southern subtropical Pacific. Records run from about 640 m down to roughly 1591 m. It holds its place in the water column rather than swimming hard, watching with large eyes for prey to pass.