Nannopetersius is a genus of African tetras in family Alestidae, found in Congo basin and Gulf of Guinea coastal river systems - the atlas records it from Gabon, Angola, Cameroon, the Democratic Republic of the Congo, Equatorial Guinea, and the Republic of the Congo. Atlas species run about 3–4.5 in, sharing the streamlined, silvery, laterally compressed body typical of Alestidae, the same family that includes the popular Congo tetra.
None of the three atlas species has an established presence in the aquarium trade under this genus name, and detailed husbandry accounts are not readily available; general Alestidae care - soft, slightly acidic water, open swimming space, and a schooling setup - would be the reasonable starting point if any were offered. Two of the three atlas species are assessed as Least Concern and the third has not been evaluated, so there is no flagged conservation concern for the genus as currently understood.