Original description as Xiphophorus pygmaeus:
ZooBank:7EA07A04-488D-4853-A1C1-EC49B65A595A.
- Hubbs, Carl Leavitt & M. Gordon. 1943. "Studies of cyprinodont fishes. XIX. Xiphophorus pygmaeus, new species from Mexico". Copeia. 1943(1):31-33 (ffm00064)
Conservation: Xiphophorus pygmaeus is evaluated by the international union for the conservation of nature in the iucn red list of threatened species as (DD) data deficient (2018). Although the Huichihuayan and Axtla rivers carry enough flow and most areas remain in very good shape, with some remaining pristine areas, increasing deforestation, pesticides and fertilizers use, and pollution (particularly around Huichihuayan) are common problems that affect them and have to be resolved, particularly given human population increase in the area. During the past years, I have seen an increase in the amount of green algae in the rivers, which was rare before.