Rare Eyeless Mexican Catfish Found in Texas Cave

Two endangered blind catfish found in a cave in Texas were previously only known to exist in Mexico. Danté Fenolio

In a Texas cave, scientists have discovered an extremely rare eyeless fish previously known to exist only in a small area of Mexico. The creature, known as the Mexican blindcat (Prietella phreatophila), is neither a cat nor, as it turns out, solely Mexican, but it is indeed sightless: It lives in the complete darkness of underground streams and pools, where it has no need for eyes.

"Cave-dwelling animals are fascinating in that they have lost many of the characteristics we are familiar with in surface animals, such as eyes, pigmentation for camouflage and speed," said biologist Peter Sprouse Zara in a statement. "They have found an ecological niche where none of those things are needed, and in there they have evolved extra-sensory abilities to succeed in total darkness."

Some of these talents include the capacity to find prey by sensing small electrical fields put off by their bodies.

Jack Johnson, a caver and National Park Service resource manager, first found the fish in April 2015 at the Amistad National Recreation Area near Del Rio, Texas, west of San Antonio, but couldn't relocate it on subsequent trips. In May, he led a team which rediscovered two specimens and positively identified the creature, Dean Hendrickson, curator of ichthyology at the University of Texas at Austin, said in a statement that he's "seen more of these things than anybody, and these specimens look just like the ones from Mexico."

The presence of the pinkish, 3-inch-long fish in the Amistad indicates a high likelihood that in the Edwards-Trinity Aquifer, which stretches from Mexico to San Antonio and encompasses the park, there exist the water-filled, underground passages the animal uses to move about.

There are now three known types of blind catfish in the United States, all found in Texas. Besides this new fellow, the state is also home to the toothless blindcat (Trogloglanis pattersoni) and the widemouth blindcat (Satan eurystomus).