(cusk eels), a genus of marine fishes of the order Perciformes. There are several species, found in coastal waters of the Mediterranean and contiguous Atlantic waters. The USSR has one species, O. rochei, which dwells in the Black Sea. The species reaches a length of 25 cm. It lives near the bottom, burrowing into the sand during the day and assuming a vertical position. The fish buries the posterior end of its body with undulating movements of its long, unpaired fins. O. rochei is active during the night, when it feeds on benthic invertebrates and fishes. Spawning occurs from June to September; the roe are pelagic.