Priocharax is a genus of extremely small tetras in the family Characidae, native to Amazonian river systems in Brazil, Colombia, and Peru. It is one of the smallest-bodied genera in the entire atlas: recorded adult sizes run from roughly 0.5–1 in, placing several of its species among the tiniest known vertebrates. Like a number of other diminutive Amazonian characins, at least some Priocharax species reach their small size partly through developmental truncation, maturing and reproducing while retaining juvenile, only partly ossified skeletal features rather than passing through a full adult developmental sequence. The atlas covers 13 species.
Priocharax is essentially a genus of scientific rather than aquarium interest: none of its species carry established common names in the trade, and their minute size and apparent ties to soft, often blackwater Amazonian habitats make them impractical aquarium subjects even for specialists. Conservation data for the genus are correspondingly sparse — the large majority of atlas species are not yet formally assessed by the IUCN, consistent with a group of tiny, recently documented fish from remote headwater and floodplain habitats that have had limited survey coverage.