Diagnosis: teeth in jaws with shafts as in O. niloticus niloticus or a little more slender, in 3 or 4 series up to about 160mm SL, 4-6 above this size; outermost all bicuspid, rarely 1 or 2 with a third cusp; lower pharyngeal teeth usually finer and more numerous than in O. niloticus niloticus, and on a smaller dentigerous area with concave sides, its median length always less than that of the blade; width of bone equal to or a little greater than its length, 29.0-33.4% head length; vertical stripes on caudal fin usually distinct, with anastomoses only basally; breeding males with throat, chest, pelvic, dorsal and anal fins black, head and flanks flushed red (Ref. 2).

Description: dorsal head profile straight (Ref. 1887) or slightly convex (Ref. 1887, 54979). Snout rounded (Ref. 1887). Jaws equal anteriorly (Ref. 55985). Maxillary not reaching anterior margin of eye (Ref. 1887, 51936, 53528, 55985, 72417). 2 (Ref. 1887, 51936, 53528, 55985, 72417) or 3 (Ref. 1887) scale rows on cheek. Maxillary entirely covered by preorbital (Ref. 72417). Gill rakers short (Ref. 1887). Inferior vertebral apophysis (spondylophysial apophysis) of only the third vertebra supports anterior end of swimbladder (Ref. 2). 11-15.5 scales between upper part of lateral line and pelvic fins (Ref. 51936, 54979). 19-22 scales in upper part of lateral line, 11-18 in lower part (Ref. 1887, 51936, 53528, 72417). 5-7 scales between pectoral and pelvic fins (Ref. 55985). Pectoral reaching beyond vertical of origin of anal (ref. 1887). Pelvic fins reaching vent (Ref. 51936, 55985, 72417) or not (Ref. 53528). Soft rays of dorsal fin longer than spines (Ref. 53528). Soft dorsal reaching caudal fin (Ref. 54979). Third anal fin spine a little longer than last dorsal (Ref. 55985). Caudal fin a little covered by scales, with straight posterior margin and slightly rounded corners (Ref. 54979).

Coloration: vertical bars on caudal fin sometimes absent and replaced by white dots (Ref. 54979, 55074), arranged in vertical or oblique rows (Ref. 54979). Blackish opercular spot present in both sexes; vertical fins with alternating series of pale and dark spots on the soft part (Ref. 72417). Male (in live): body grey-brown with a greenish hue above; mature males with darker head, reddish upper part of cheeks, bluish-black lower part of cheeks and throat, and rosy chest with dark grey-blackish spots and lines; dorsal, anal and pelvic fins blackish; pectoral fins red; caudal fin reddish with numerous black, vertical, wavy lines, sometimes replaced by rows of white spots (Ref. 54979). Gill membrane of male blackish, sometimes also on inferior parts of head (Ref. 72417). Females and young: body paler, greenish, relatively dark above becoming paler ventrally; throat white; chest rosy-whitish; belly whitish; cheeks dark green above; opercular spot clearly visible (Ref. 54979). Gill membrane of females yellowish or with small blackish spots (Ref. 72417). Juveniles with about 10 vertical bands dorsally, a black lateral spot below the dorsal fin extremity and a spot on the upper part of the caudal peduncle; soft part of vertical fins with dark spots forming parallel lines (Ref. 53528). Preserved fish: generally green-grey or grey-brown, with paler fins; caudal fin greyish with black vertical stripes (ref. 54979). Pelvic fins dark, except near inner edge; soft anal dark at base (Ref. 55985). Body with or without very indistinct darker cross-bars; soft dorsal uniform or with oblique streaks (Ref. 1887).