The black ruff (Centrolophus niger) is a medusafish, the only member of the genus Centrolophus. It is a bathypelagic fish found in all tropical and temperate oceans at depths of 50 to 1,000 m (160 to 3,280 ft). Its length is typically up to 60 cm (24 in), but it may reach 150 cm (60 in). Other common names include rudderfish and blackfish.
The black ruff has a robust fusiform body shape. Its maximum length is 150 cm (60 in) but a more common length is 60 cm (24 in). The dorsal fin has five spines and 37 to 41 soft rays, the anal fin has three spines and 20 to 24 soft rays. The bases of these fins have a fleshy sheath clad with scales that partially conceals the rays. The head is grey and the body colour violet-black, dark brown or purplish, with a paler belly. The fins are darker than the body colour. Sometimes there are indistinct spots or a marbled pattern.[2][3]
The black ruff is known from the northwestern Atlantic Ocean, where its range extends from Nova Scotia to Massachusetts, the northeastern Atlantic and the Mediterranean Sea; also from the southeastern Atlantic and the Indian Ocean, its range including South Africa and Australia and New Zealand, as well as the Southern Ocean. It is a bathypelagic fish with a depth range of 40 to 1,050 m (130 to 3,440 ft), but is usually found within the range 300 to 700 m (1,000 to 2,300 ft). It is largely absent from the tropics.[2] It is occasionally found in the waters around the British Isles, where it has been recorded off County Galway, County Donegal and the Isles of Scilly. In 1901, a specimen was caught in a salmon net in the Firth of Forth and was presented to the Edinburgh Museum.[3]
Juvenile fish live in surface waters but adults live at greater depths where they may form small schools. The diet consists mainly of small fish, squid, large crustaceans, and any other animals that may be encountered in mid-ocean.[2]
The black ruff (Centrolophus niger) is a medusafish, the only member of the genus Centrolophus. It is a bathypelagic fish found in all tropical and temperate oceans at depths of 50 to 1,000 m (160 to 3,280 ft). Its length is typically up to 60 cm (24 in), but it may reach 150 cm (60 in). Other common names include rudderfish and blackfish.
