For instance, Lake Dissoni/Soden, a small volcanic lake covering an estimated , is located at the southeastern slopes of the Rumpi hills. The lake flows into a stream that eventually empties into the River Meme. There are only three fish species in the lake which are all endemic including Poeciliid (Procatopus lacustris) which may be related to Procatopus similis more abundant in surrounding rivers, streams and lakes. An undescribed catfish (Clarias spp) and barb (Barbus spp) as well as the atyid shrimp Caridina sodenensis are endemic species to this lake.