Females and immatures are a silvery grey, but show little sign of vertical bars on the flanks or a 'tilapia mark' at the base of the soft dorsal fin shown by most other tilapias.

[3] The species was described as Tilapia amphimelas by Franz Martin Hilgendorf at the Natural History Museum, Berlin in 1905 from male specimens collected from Lake Manyara by Oscar Neumann between 1893 and 1895.

The name, meaning 'double-black', probably refers to the dark upper and lower fins of the breeding male.

[3] Genetic evidence published in 2019 supported earlier theories, indicating that O. amphimelas (along with O. esculentus) is closer to Alcolapia than it is to other Oreochromis.

Females appear to grow larger than males, which is unusual in Oreochromis and cichlids in general.

The water level varies between seasons and years, leading to marked fluctuation in salinity and alkalinity.