Original description as Limia formosa:
- Girard, Charles Frederic. 1859. "Ichthyological notices". Proceedings of the Academy of Natural Sciences of Philadelphia. 11:113-122 (ffm04560)
Conservation: Poecilia formosa is evaluated by the international union for the conservation of nature in the iucn red list of threatened species as (LC) least concern (2019). Listed as Least Concern given the large range of this species spanning from The Rio Bravo basin southward to Laguna Tampamachoco near Tuxpan, the large number of subpopulations, and the lack of major threats. The trend over the past 10 years or three generations is uncertain but likely relatively stable, or the species may be declining but not fast enough to qualify for any of the threatened categories (NatureServe & Daniels, 2019).