The African lake home to the largest cichlid fish species flock, with more than 500 endemic species, is Lake Malawi.
Lake Malawi, also called Lake Nyasa, occupies a long rift-valley basin between Malawi, Mozambique, and Tanzania. Its isolated waters allowed cichlids to diversify into an extraordinary range of forms, colors, diets, and behaviors. Current estimates identify at least 700 cichlid species in the lake, although the exact total remains uncertain because many species are difficult to distinguish and some have not been formally described.
Nearly all of Lake Malawi’s cichlids are endemic to the Malawi system, meaning they occur naturally nowhere else. Many are mouthbrooders: the female carries fertilized eggs or young in her mouth, protecting them from predators. This evolutionary radiation has also made Malawi cichlids popular aquarium fish.
Lake Victoria is another African lake famous for a huge endemic cichlid radiation, so it is a tempting alternative. Lake Malawi is the stronger answer here because its flock is generally recognized as the larger and better-documented concentration, with hundreds of endemic species still living in the lake’s rocky shores, reefs, and open waters.