Oreochromis

The soda cichlid, Alcolapia alcalica, is endemic to Lake Natron in Tanzania, a shallow soda lake full of hot, alkaline springs. The lake runs at pH 9.5-10.5 and 32-43.5 °C, and though captive fish can be acclimatised to more normal conditions, this must happen slowly, with the pH kept above 8.0 and the temperature at 28 °C or more. Exceptionally rare in the hobby, it excretes urea where most fish excrete ammonia, and periodically gulps air at the surface.

Graham's soda cichlid, Alcolapia grahami, is endemic to Lake Magadi in Kenya, a shallow soda lake full of hot, alkaline springs. It lives around the spring inlets and lagoons of the shoreline in water of pH 9.5-10.5 at 32-43.5 °C, and excretes urea where most fish excrete ammonia. Exceptionally rare in the hobby, it can be acclimatised slowly to more normal conditions, but the pH should not drop below 8.0 or the temperature below 28 °C.

The Mozambique mouthbrooder, Oreochromis mossambicus, is a cichlid native to the East African coast and one of the most invasive fish in the world. Farmed for food across the globe, it now has escaped populations in over 90 countries. Known in the trade as the 'Mossie', it reaches 39 cm, breeds readily in large broods and is not recommended to most hobbyists. The brightly coloured forms seen in aquaria are selectively bred, and some are crosses with other Oreochromis.

The Nile tilapia, Oreochromis niloticus niloticus, is a cichlid with a very wide natural range in Africa, from Senegal east to Egypt and Uganda. Bred in huge numbers as a food fish, it has been introduced to over 70 other countries and is one of the most invasive fish species in the world. It reaches 60 cm, though usually around 35 cm, breeds readily, is very messy and does not make a good aquarium subject.

The Tanganyikan tilapia, Oreochromis tanganicae, is a large cichlid endemic to Lake Tanganyika, where it inhabits river mouths and shorelines. It is often seen in shoals in nature and appears to feed primarily on phytoplankton. Reaching 42 cm, it is not seen very often in the hobby.