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 42cm (17inches) in length, the dragon poacher (Percis japonica) is the largest member of the family, while Bothragonus occidentalis is 7cm (03inches) 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 1280m (4,200feet) deep, with only a few species preferring shallower, coastal waters. All but one species are restricted to the Northern Hemisphere.[1]
The family Agonidae was first proposed as a family in 1839 by the English naturalist William John Swainson.[2] The Agonidae is classified within the superfamily Cottoidea in the suborder Cottoidei in the order Scorpaeniformes in the 5th edition of Fishes of the World but other authorities states that if Scorpaeniformes is excluded from Perciformes then Perciformes is recovered as paraphyletic and so classify this family within the infraorder Cottales within the suborder Cottoidei of the Perciformes.[3] A number of taxa which were previously classified within the Cottidae were reclassified within the Agonidae which meant that the Cottidae was confined to the freshwater sculpins.[4]
The Agonidae is divided into the following subfamilies and genera:[5] [2]