Species: Oreochromis niloticus, Nile Tilapia

Oreochromis niloticus (Linnaeus, 1758)

Nile Tilapia

Body an elongate oblong; 1 pair of nostrils; top jaw highly protrusible; jaws of mature males are enlarged, resulting in a concave forehead; teeth fine, close set, in several rows on jaws, 3-5 rows, outer row 2-pointed, outer row readily movable; fine teeth on throat plate that is longer than wide; gill rakers simple, lower rakers 20-21 (19-26); one dorsal fin XVII (XVI-XVIII), without a notch between spines and rays, 12 (10-14), longest soft ray extending onto base of tail in female and ¾ of tail in male; anal fin III, 9-12; tail fin straight; scales large, 2-3 horizontal rows on cheek, 4-5 rows between dorsal origin and lateral line; tail fin not densely scaled; lateral line in 2 straight overlapping sections, with 32-33 (30-34) scales; genital papilla large, elaborate.

Female and non-breeding male: silvery gray, sometimes indistinct dark bars; a dark blotch at top rear corner of operculum; tail fin covered with 7-12 narrow dark bars. Juveniles with a large dark, whitish edged spot on base of front dorsal soft fin rays, body with ~9 dark bars, opercle with a dark spot. Breeding male: grey body and fins; head, tail fin and front of dorsal fin with a reddish cast.

Reaches 60 cm.

Lives in fresh and brackish water.

Depth range: 0-5 m.

Originally from SE Africa; introduced widely throughout our region for aquaculture purposes.