Shire tilapia

Dorsal spines (total): 15-18; Dorsal soft rays (total): 10-13; Anal spines: 3-5; Anal soft rays: 9-11; Vertebrae: 29-30. Diagnosis: A large, deep-bodied species with 4, rarely 3 or 5, anal fin spines (Ref. 118638). Females and immatures from the Lake Malawi catchment have a dark olive-coloured body, yellow-gold below; other populations, such as those from Lakes Chilwa and Chiuta and the Ruvuma system show a more silvery colour; unusually for Oreochromis, the horizontal stripes are often more prominent than the vertical bars; adult males develop very large jaws and a concave head profile, they are black, with red margins to the dorsal and caudal fins (Ref. 118638). Underwater or in aquaria, males show numerous white spots on the upper half of the flanks, but these fade quickly under stress, so that they appear uniformly black when removed from the water (Ref. 118638).