Mexican Cavefish Populations (IMAGE) Florida Atlantic University Caption A. mexicanus exist as surface fish that inhabit rivers in Mexico and Southern Texas and as more than 30 geographically isolated cave?dwelling populations of the same species. Credit Florida Atlantic University Usage Restrictions Credit: Florida Atlantic University License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.