Nannocharax is a genus of small African characins in the family Distichodontidae, sometimes called African darters for their habit of perching on the substrate rather than swimming freely in open water. The atlas covers 41 species, all small — from 1 in up to 3 in — with an elongated, often strikingly barred or striped body and a small, ventrally positioned mouth adapted for grazing algae and biofilm off rocks and wood in flowing water, a lifestyle that echoes hillstream loaches on the other side of the world despite the two groups being unrelated. Atlas records come from Central and southern Africa, including the Democratic Republic of the Congo, Cameroon, Angola, the Republic of the Congo, Zambia, Gabon, Namibia, and Botswana, tracking the genus's spread across the Congo basin and neighbouring river systems.
Nannocharax is little known in the aquarium hobby — its species tend to be modestly coloured, current-loving stream fish that demand well-oxygenated, flowing water rather than a typical community tank, so interest runs more toward ichthyology than the trade, with the barred nannocharax (N. fasciatus) and slender African characin (N. gracilis) among the few species that occasionally surface in specialist circles. Conservation status is reasonably settled for the group as a whole: the atlas tally shows 19 of the 41 species Least Concern, though 15 remain Not Evaluated, underscoring how much of the Congo basin's smaller stream fauna has still not been formally assessed despite the region's overall biodiversity being well documented.