Idiacanthus atlanticus, the black dragonfish, is a barbeled dragonfish of the family Stomiidae, found circumglobally in southern subtropical and temperate oceans between latitudes 25°S and 60°S, at depths down to 2,000 metres. The Black Dragonfishes are long, slender fishes that are sexually dimorphic. The image shows a female with its small eyes, chin barbel, and long fang-like teeth. The male is much smaller. It lacks teeth, lacks the chin barbel, has a non-functional gut, and is dark brown rather than black. The large teeth of the dragonfish help it to grab its prey as it hunts in the dark waters of the deep sea. It will feed on small fish and crustaceans as well as anything else it can find. The black dragonfish faces danger from the red flounder fish that is found on the ocean floor. Because they live in extremely deep waters, very little is known about the mating habits of the dragonfish. It is believed that they are external spawners, meaning that the female releases eggs into the water to be fertilized by the male. The eggs then float to the surface where they remain until hatching. Once the eggs hatch, the tiny larvae are left to fend for themselves until they can reach maturity. Once mature, they return to the deep ocean to spend the rest of their lives. Not much is known about the life span of the dragonfish.