Alestopetersius is a genus of small African tetras in the family Alestidae, the same family that includes the true Congo tetra, Phenacogrammus interruptus, though the two genera are distinct. The atlas's 12 species are drawn from Central African rivers in the Democratic Republic of the Congo, the Republic of the Congo, and the Central African Republic, and from West African rivers in Cameroon and Nigeria. They are slender, laterally compressed schooling characins with the typical adipose fin of the group, and several species develop elongated dorsal or caudal fin rays in mature males alongside strong iridescent coloring.
African-tetra specialists value Alestopetersius for the brilliant blue, violet, or yellow sheen its species can show under the right lighting in soft, blackwater-style water. Named species in the atlas include the African Blue Tetra, Bleher's Tetra, Brichard's Tetra, Yellowtail Tetra, Leopold's Tetra, African Rainbow Tetra, Blue Diamond Tetra, and Banded African Tetra, several honoring the collectors and ichthyologists associated with their discovery. Conservation is mostly reassuring, with 7 of 12 species Least Concern, though 2 Endangered and 2 Data Deficient species show that a handful of more range-restricted populations carry genuine concern.