Elachocharax is a genus of tiny darter characins in family Crenuchidae, found in blackwater streams and leaf-litter habitat across the Amazon, Orinoco, and Guiana Shield drainages, with atlas records from Brazil, Colombia, Venezuela, Guyana, and Peru. These are among the smallest freshwater fish in the atlas: the four species run just 0.5–1 in as adults, slender and cryptically patterned to blend into submerged leaf litter, where they perch near the bottom in the darter-characin manner rather than swimming continuously in open water.
This is a genus of mostly scientific interest rather than mainstream aquarium appeal — only the black pygmy darter characin (Elachocharax pulcher) carries an English common name in the atlas, and the genus's extreme small size and specialized blackwater, leaf-litter requirements keep it firmly in specialist-biotope territory rather than the general trade. Conservation data are sparse: three of the four atlas species have not yet been formally assessed, and only one carries an IUCN rating (Least Concern) so far — typical for a genus of tiny, hard-to-survey fish spread across a vast and remote range.