Lake Malawi is the third deepest lake in the world and is inhabited by the largest assembly of fish species of any lake on earth: about 875 species of cichlids, most of them endemic.
The Cichlids of Malawi are fish from the family Cichlidae in the order Perciformes. These fish are members of a group known as the Labroidei which is both extensive and diverse. At least 1,650 species have been identified and classified to date, with many more still either unknown, or undiscovered.
They occur in tropical waters and apart from a series of anatomical features, are characterized by the fact that they give care to their offspring by ‘mouth-brooding’ which is act of carrying young in the mouth until such times as they are ready to swim and fend for themselves.
Due to the fact that Lake Malawi is heavily isolated from other seas’, oceans and other water bodies, the lake is an outstanding example of biological evolution. Adaptive radiation and specification are particularly noteworthy in the small brightly colored rocky-shore tilapiine cichlids (rockfish), known locally as Mbuna. The rocky habitats in Lake Malawi occur in a checkered pattern and some rocky shores are separated from neighboring rocky outcrops by long stretches of sandy shores, too long for rockfish to cross. Over time, each rocky shore acted like an isolated island where the rock-dwelling fish evolved into new species without the influence of those in "neighboring islands".
Lake Malawi has a healthy population of many different species of Cichlids but the actual number is still a work in progress. Identifying a Cichlid in Lake Malawi is a difficult art as they are highly diverse in terms of size, coloration, behaviour, and ecology. With enough practice however, their distinct markings and characteristics will become more recognizable.
*sources: Ad Koning, Cichlids of Lake Malawi National Park and UNESCO