Sloane’s viperfish, Chauliodus sloani, is a dragonfish[disambiguation needed of the genus Chauliodus, found in all tropical and subtropical oceans, at depths down to 2,500 m. Their length is between 20 and 35 cm.
As a species, Sloane’s viperfish holds the world record for largest teeth relative to head size in a fish. It has teeth so large that it must open its mouth to make the jaws vertical before it can swallow prey. When the mouth is closed, the teeth overlap the jaws. It eats large prey by lowering the internal skeleton of the gills, allowing the prey to pass into the throat without interference. It can impale prey on the teeth by swimming at them with the first vertebra behind the head acting as a shock absorber. Sloan’s viperfish is approximately 28 cm (11 in) long. Its head is about 2 cm (0.8 in) and its teeth are just over half this length.