Technology was developed to produce all male, sex-reversed tilapia (SRT) seed, because male tilapia grow faster than females, and the unwanted reproduction, overcrowding, and harvest of undersized fish are avoided.9 These advances boosted production of farmed tilapia and masked the lack of attention to their genetics in the 1970s and 1980s. As an indication of this, up to the late 1980s, most aquaculture researchers described their tilapia populations only by species name, with little or no documentation about their provenance and breeding histories