M Is For Monterrey Platyfish

Monterrey Platyfish
Xiphophorus couchianus

Where it lived: Parts of the Rio San Juan near Monterrey, Neuvo León, Mexico, including in the Apodoca, Monterrey, and Santa Catarina rivers

Last seen in: The species is extinct in the wild, with “safety populations” held at Mexico’s Universidad Autonoma de Nuevo Leon, at the Texas State University Institute for Molecular Life Sciences, and by some private aquarists. The species was last collected in its native habitat in 1967.

Declared extinct in the wild by IUCN in: 2018

Threats:

  • Habitat loss from the over-extraction of water resources

  • Pollution from urban sewage and run-off

  • Competition from introduced species

With the growing sprawl of the Monterrey, Mexico, metropolitan area, the native Monterrey Platyfish saw its habitat shrink and, in some cases, disappear entirely. As Rit Forcier of the American Livebearer Association put it:

“Once an important source of water and recreation, [Huasteca Canyon] is now just a dry park near the center of town. As the story goes, the town grew and the people needed more drinking water. As more wells were dug and more water consumed, the spring actually shrunk. It dried up completely in the 1990s, and the Monterrey platy Xiphophorus couchianus is now completely gone, except for those in public aquaria or the tanks of fishkeepers.”

Now, this fish’s survival depends on ex-situ conservation efforts—those efforts that take place outside of a species’ natural habitat. Thanks to two universities and some individual hobbyists, the Monterrey Platyfish has yet to face complete extinction. But it will take long-term dedication and financial resources to maintain these safety populations and policy changes to restore the river systems before the species may be re-introduced to its native waters.