Spinyfins are a family, Diretmidae, of trachichthyform fishes. The family name is derived from the type genus, Diretmus, from Greek, di meaning "two" and eretmos meaning "oar". They are found worldwide in deep waters, as deep as 2,000 m (6,600 ft). As the common name implies, spinyfins have heavy spines along their fins. They have deep, compressed bodies, and almost vertically aligned mouths. They are dark silver in colour, and reach up to 37 cm (15 in) in length.