Nanochromis transvestitus is a sexually dimorphic cichlid

Cichlid

Cichlids are fishes from the family Cichlidae in the order Perciformes. Cichlids are members of a group known as the Labroidei along with the wrasses , damselfish , and surfperches . This family is both large and diverse. At least 1,300 species have been scientifically described, making it one of...

 from river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

ine west Africa

West Africa

West Africa or Western Africa is the westernmost region of the African continent. Geopolitically, the UN definition of Western Africa includes the following 16 countries and an area of approximately 5 million square km:-Flags of West Africa:...

. Unusually for cichlids, it is the female not the male that is the most colourful. The female has a vertical black and white banding on her anal and caudual fins, with a bright red abdomen. The male, by contrast, is grayish in colour. Like many cichlids, the male does, however, have longer anal and caudal fins. The fish are egg layers and make a nest in the substrate

Substrate (aquarium)

The substrate of an aquarium refers to the material used on the tank bottom. It can affect water chemistry, filtration, and the well-being of the aquarium's inhabitants, and is also an important part of the aquarium's aesthetic appeal...

in which to lay their eggs.