Cichlids of the Rift Lakes : the extraordinary diversity of cichlid fishes challenges entrenched ideas of how quickly new species can arise

dark and deep, but the shallow, sunlit edges are where most of the cichlids live. Brown or green Eretmodus algae scrapers, covered with blue spots, thrive among the breaking waves; the turbulent water pushes their rounded backs onto the rock surfaces instead of pulling them off. These fish nip algae off the rocks with their chisel-like teeth. Their neighbors the Tanganicodus insect pickers also have round backs. But the pointed heads, sharp snouts and long, fine teeth of these cichlids are adapted to plucking insect larvae from within the crevices. In calmer waters, old snail shells are strewn on