Morphology: Dorsal spines (total): 16 - 18; Dorsal soft rays (total): 9 - 11; Anal spines: 3 - 4; Anal soft rays: 8 - 11; Vertebrae: 29 - 30. Diagnosis: about 50% of individuals with 4 anal fin spines; modal numbers of vertebrae (29), dorsal rays (27) and gill-rakers (15) low; jaws of breeding males enlarged; females and non-breeding males with horizontal and vertical elements of melanin pattern conspicuous, especially at their junctions, where blotches are often drawn out vertically (Ref. 2). Breeding males with throat and chest black (Ref. 2), and conspicuous broad dark vertical bars on the lower half of the body (Ref. 2, 4967, 54096). Description: 3-5 series of teeth, outer bicuspid or with reduced or absent minor cusp in breeding or recently spent males, inner tricuspid (Ref. 2). Tooth band wide (Ref. 4967, 55060). Males with large mouth and thick lips (Ref. 4967). Maxillary extending nearly to below eye in some males; lower pharyngeal bone with blade as long as or a little longer than toothed area, which has concave sides and fine teeth; 2 occasionally 3 rows of scales on cheek; 4-6 scales between bases of pectoral and pelvic fins; scales small on chest (Ref. 2). Long dorsal and anal fins; pectoral fins short, not reaching anus (Ref. 55060). Pelvic fins drawn out into a long filament in mature males; genital papilla in both sexes small and flanged (Ref. 2). Coloration: In alcohol: Females and sexually inactive males: 2 rows of dark spots on sides, one at middle and one above upper lateral line (Ref. 4967, 55060). Basic melanin pattern very strongly marked; horizontal and vertical bands usually represented by intense black blotches, which may be contiguous (Ref. 2). Indications of about 7 vertical black bars across lower horizontal band; anal and pelvics and ventral surface of body dark grey; Tilapia-mark an oval black spot near hind end of dorsal fin (Ref. 55060). Blotch on top of caudal peduncle usually well-marked (Ref. 2, 55060). Caudal fin may be immaculate dark grey (Ref. 2, 55060) or may have part of its area crossed by vertical bars or series of spots; branchiostegal membrane pale; genital papilla white (Ref. 2). Males: 2 rows of dark spots on sides, one at middle and one above upper lateral line (Ref. 4967, 55060). Sometimes with stronger vertical bars on lower half of body; spaces between vertical bars, and an uneven and variable area on the operculum, may be whitish silver or aluminium-coloured (Ref. 2). Indications of about 7 vertical black bars across lower horizontal band (Ref. 55060). Branchiostegal membrane black (Ref. 2). Genital papilla white (Ref. 2, 55060), conspicuous against dark background (Ref. 2). Tilapia-mark an oval black spot near hind end of dorsal fin; black spot on dorsal side of caudal peduncle; anal and pelvics and ventral surface of body dark grey; mature males with white or grey tip to caudal fin (Ref. 55060). In life: Breeding males: no marked breeding dress; corner of caudal fin white (Ref. 2). Lower lip pale, but lower parts of head and branchiostegal membrane very dark or black; no yellow colour on flanks, belly or caudal fin, and no sky-blue areas on dorsal and anal fins (Ref. 54096). Sexually inactive males: a general dark iridescent blackish green colour, more green and iridescent on the snout; narrow red margin along the length of the dorsal fin (Ref. 2).

Max size: 20.8 cm SL (male/unsexed; Ref. 2)