How did 500 species of a fish form in a lake? Dramatically different body clocks Animals are remarkably diverse in their sleep and activity patterns due to foraging strategies, social behavior and their desire to avoid predators. With more than 3,000 types of cichlids, these freshwater fish may just be one of the most diverse species in the world. Lake Malawi alone, which stretches 350 miles through eastern Africa, is home to more than 500 cichlid species. They evolved from a few species that likely entered the lake about 3 million years ago and now display very different behaviors and inhabit well-defined niches throughout the lake.