This fish can reach up to almost 5 inches in length. It has a diet of crustaceans, insects and aquatic worms. It lives in freshwater caves in the Rio Grande, other rivers in TX and central and eastern parts of Mexico.  These fish have lost their sense of sight. But this ability is not important for their livelihood. They live in pitch-black caves where there are very few predators. They have the ability to detect vibrations by a kind of sonar like a bat's echolocation which produces sound waves that bounce off objects around them. This skill coupled with a very sensitive lateral line keep them moving, feeding and becoming prey.

Exhibit: World of Water, Discovery Caverns