Genetic tests are showing some interesting things. Outwardly, it is nearly impossible to tell the Wami (AKO O. horonorum or O. hororum) from O. mossambica. Genetic tests show that they O. auria and O. horonorum are more closely related and share a similar sex determionation. O. niloticus uses the common XX, XY sex gentics. O. auria and O. horonorum use ZZ, WZ. This is why interspecies crosses can produce all male hybrids.

Unfortunately, nearly all the aurea or horonorum available are no longer pure enough to produce all male fish.