The name Aphyosemion can be divided into two parts. Aphye is derived from Greek and means “little fish”. Semeion means “with flag” or “pennant”. This is a reference to the elongated fin rays of the dorsal and anal fin. The name Mengila is a reference to the driver and guide François Mengila from Gabon.
The males of the Aphyosemion mengilai have a bluish ground color with red spots. The dorsal and anal fins are blue which is edged with a black band. This black band also distinguishes it from the other species that look a lot like this Aphosemion. Aphyosemion grelli most closely resembles this species; however, Aphyosemion mengilai has more fin rays in the anal and dorsal fin. Another distinction is length. Aphyosemion mengilai can reach a total length of about 5 centimetres whereas Aphyosemion grelli does not grow longer than about 4 centimetres.
Aphyosemion mengilai comes from a small area in Gabon. They inhabit the basin of the Ikoy River which flows through the Chaillu Massif in Gabon. They inhabit the small shallow streams with muddy bottoms and mostly leaves on the ground.
John de Lange