Procatopus is a genus of small egg-laying killifish relatives from the forest streams of West and Central Africa, with atlas records from Cameroon, Nigeria and Equatorial Guinea. The atlas covers 3 species, all small fish topping out around 2.5 in. They belong to the lampeye group, named for a striking iridescent patch across the upper part of the eye that catches the light like a tiny mirror, a feature that makes them instantly recognisable among African killifish relatives even to casual observers.
Unlike the seasonal 'annual' killifish that lay drought-resistant eggs to survive a dry season, Procatopus species live in permanent, flowing forest streams and lay eggs continuously without a diapause stage, closer in that respect to livebearing relatives than to the classic annual killifish life cycle. Procatopus aberrans (blue-green lampeye) and Procatopus nototaenia (large finned lampeye) are the species most likely to turn up with specialist killifish keepers, prized for their colour and active shoaling behaviour in a planted, gently flowing aquarium. Procatopus similis rounds out the genus. Two of the three species are rated Least Concern by the IUCN and one is not yet evaluated, and none currently carry a CARES designation.