Priocharax pygmaeus is a minute species of freshwater ray-finned fish belonging to the family Acestrorhamphidae, the American characins. This fish is found in the Upper Amazon River basin in Colombia. It has also been recorded from the Río Ucayali basin in Peru.Toledo-Piza, M., G.M.T. Mattox and R. Britz, 2014. Priocharax nanus, a new miniature characid from the rio Negro, Amazon basin (Ostariophysi: Characiformes), with an updated list of miniature Neotropical freshwater fishes. Neotrop. Ichthyol. 12(2):229-246. The species, which has a skeleton of cartilage, is almost completely transparent.Weitzman, S.H. and R.P. Vari, 1987. Two new species and a new genus of miniature characid fishes (Teleostei: Characiformes) from northern South America. Proc. Biol. Soc. Wash. 100(3):640-652.
Size This species reaches a length of .
Etymology The fish's name is Latin for "dwarfish".
Biology Priocharax pygmaeus inhabits rainforest streams that are shaded or partially shaded. The bottom of the streams are clay with a lot of leaf litter, and submerged plants are not present.
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