There have been three species of tilapia introduced to Australia, the Mozambique tilapia, the black mangrove cichlid and the redbelly tilapia. These are all considered pest species and of these the Mozambique tilapia poses the greatest threat to native fish. Tilapis should never be released iinto any waters deaqd or alive, even when caught tin the same water, rather they should be removed permanently from the water. Even dead Mozambique tilapia may still present a threat as they are mouth brooders and experiments have shown that the young can survive for up to 14 days in the moths of dead parents.
Populations have become established in waters in the far NSW north coast, in southern and northern Queensland as well as north of Geraldton in Western Australia. This species poses the greatest risk to the Murray Darling basin as it has been recorded only three kilometres from the headwaters of some MDB streams.
Black mangrove cichlid
Pelmatolapia mariae, formerly Tilapia mariae
In Australia usually called just "tilapia", these fish were originally introduced as tropical aquarium fish. Illegally released into the Hazelwood power station pondage they have been able to establish a self sustaining population in the heated waters of the pondage. Due to the lower water temperatures in other Victorian waters, it is considered unlikely that tilapia will establish populations outside the pondage and due to the recent closure of the Hazelwood power station the likelihood of this population surviving is questionable.
However, tilapia pose a substantial threat in the warmer waters of Northern Australia and have been found in recent years in northern Queensland around Cairns.