Located in the southern part of the great rift valley, lake is the world's longest freshwater lake and has been a showcase of cichlid evolution. many of the endemic fish have made their way into the aquarium trade.

The answer is "Lake Tanganyika".

Lake Tanganyika refers to an African Great Lake and is the second most established freshwater lake on the planet, second biggest by volume, and the second most profound, in all cases after Lake Baikal in Siberia. The water streams into the Congo River framework and eventually into the Atlantic Ocean. 

Isay b but i'm not sure.