Lake Ejagham is a small lake in Eyumojock, Cameroon's southwest region. It is not a volcanic lake, like many others in Cameroon, but rather a solution basin formed by groundwater during the last ice age. 

This remote lake is oval in shape, has no inflow, and empties into the Munaya River. Because of the water fall, most fish cannot pass through this outflow.

Despite its small size, it is home to seven endemic coptodonine and oreochromine cichlid fish species (Coptodon deckerti, C. ejagham, C. fusiforme, C. nigrans, Sarotherodon lamprechti, and S. knauerae). Six of these species were scientifically described only in 2010 and 2011. 

A catfish species from the genus Parauchenoglanis has been introduced into the lake, and this probably presents a serious threat to the endemic cichlids.

The Ejagham cichlids are widely regarded as an excellent example of sympatric speciation within its two genera. According to studies, there was some secondary gene flow between the lake's species and relatives from nearby regions, which likely aided in speciation (i.e., the Ejagham species not strictly the result of sympatric speciation).