Over generations of darkness, the subterranean fish lost the huge round eyes of their surface dwelling cousins, and the silvery pigments in their skin. They became Mexican blind cavefish.

Most people never get to see these fish, but they’re important: Their health reflects the health ... San Antonio Zoo’s Department of Conservation and Research houses some Mexican blindcats in a ...

The Mexican tetra ... in the absence of light, the blind fish in caves faced no disadvantage and could reproduce. However, a shared feature between the surface and cave forms is the Mauthner ...

To demonstrate this, they give the example of the Mexican tetra fish Astyanax mexicanus. Some populations of A. mexicanus are blind cave fish that live in darkness. Other, genetically distinct ...