Prietella phreatophila (Carranza, 1954)

The Mexican blindcat is a catfish that lives only in groundwater — up to 2,000 feet underground in the Edwards-Trinity Aquifer underlying the Rio Grande Basin in Texas and Coahuila, Mexico.

As their name implies, blindcats are eyeless. They can grow to be about 5 inches long and look pinkish because they have translucent skin that allows their blood vessels to show through. Their snout overhangs their mouth, which, along with their sharp sense of smell, helps them hunt for macroinvertebrates. Their lateral lines help them detect motion in the water, and they’ll swallow any small prey they come across, though they can survive long periods without eating.

Most people never get to see these fish, but they’re important: Their health reflects the health of the groundwater where they live. Humans are completely dependent on the groundwater supply for drinking water and other uses.

Once they were thought to live only in Mexico; their presence in Texas shows that the watershed is connected across the border and reflects the connection of human and natural communities between the two countries.

The biggest threats to the blindcat’s survival are overuse of groundwater and pollution. The rock in the aquifer is highly porous and vulnerable to contamination from agriculture, development, and fossil fuel extraction.

Mexican blindcats were protected under the U.S. Endangered Species Act in Mexico in 1970, but it weren’t discovered in Texas until 2015.

There are only four total known species of underground catfish in North America. Three of them are found in Texas: the Mexican blindcat, widemouth blindcat and toothless blindcat, each of which belongs to a different genus even though they share characteristics and habitat. Mexico is home to the Mexican blindcat and the phantom blindcat, in the same genus.

The Center for Biological Diversity is working to secure Endangered Species Act protection for the other blindcat species in Texas, the toothless and the widemouth.

San Antonio Zoo’s Department of Conservation and Research houses some Mexican blindcats in a special area for cave and aquifer species that’s closed to the public. It hopes to establish a captive-breeding population to ensure the blindcat is not lost to extinction.

Learn about the Center's Endangered Species Mural Project, now featuring a mural of the Mexican blindcat in Del Rio, Texas.

Learn about other fish we're working to save from extinction.

Photo of Mexican blindcat mural sketch by Roger Peet.