Deeply keeled, compressed bodies and large eyes typify sweepers, their form somewhat like hatchetfish both cycloid and ctenoid scales may be present. The small, short dorsal fin begins before the body's midpoint and may have four to seven spines the anal fin is extensive and usually has three spines. The mouth is subterminal and strongly oblique. Species of the genus Parapriacanthus have much more cylindrical bodies. Some species possess photophores. All but the curved sweeper (Pempheris poeyi) possess a gas bladder. The largest species is the common bullseye (Pempheris multiradiata) at 28 cm (11 in) long most other species measure 16 cm (6.3 in) or less. Colouration is relatively subdued.