The nsess (Stomatepia mariae) is a species of cichlid endemic to Lake Barombi Mbo in western Cameroon. It can also be found in the aquarium trade.[2] It is critically endangered because of pollution and sedimentation due to human activities. It is potentially also threatened by large emissions of carbon dioxide (CO2) from the lake's bottom (compare Lake Nyos),[1] although studies indicate that Barombo Mbo lacks excess amounts of this gas.[3]
The nsess can reach up to 12 centimetres (4.7 in) in standard length and is predatory; it sometimes steals prey from the freshwater crab Potamon africanus.[2]