Cutthroat eels are a family, Synaphobranchidae, of eels, the only members of the suborder Synaphobranchoidei. They are found worldwide in temperate and tropical seas. Cutthroat eels range from 23 to 160 cm (9.1 to 63.0 in) in length. They are bottom-dwelling fish, found in deep waters down to about 3,700 m (12,100 ft).