Agonidae

Agonidae is a family of small, bottom-dwelling, cold-water marine fish. Common names for members of this family include poachers, Irish lords, sea ravens, alligatorfishes, starsnouts, hooknoses, and rockheads. They are notable for having elongated bodies covered by scales modified into bony plates, and for using their large pectoral fins to move in short bursts. The family includes about 59 species in some 25 genera, some of which are quite widespread. The pelvic fins are nearly vestigial, typically consisting of one small spine and a few rays. The swim bladder is not present. At 42 centimetres (17 in) in length, the dragon poacher (Percis japonica) is the largest member of the family, while Bothragonus occidentalis is 7 cm (2.8 in) long as an adult; most are in the 20–30 cm range. Agonidae species generally feed on small crustaceans and marine worms found on the bottom. Some species camouflage themselves with hydras, sponges, or seaweed. They live at 1,280 m (4,200 ft) deep, with only a few species preferring shallower, coastal waters. All but one species are restricted to the Northern Hemisphere. An indeterminate fossil agonid is known from a nearly complete skeleton from the mid-Miocene-aged St. Marys Formation of Maryland, US, representing the earliest known member of the family.