A University of Idaho study shows exposure to the thyroid hormone can alter the colour vision of zebrafish.  

Lead author, Robert Mackin, said the findings indicate thyroid hormone can control whether red- or orange-sensitive opsin genes are activated in the cone cells of zebrafish, suggesting zebrafish may use thyroid hormones to adapt their eyesight to changes in swimming and feeding behaviours.  

As zebrafish and humans have similar colour vision genetics, the results may lead to new treatments, he said. "Our primary goal is to figure out the basic science and understand how opsin expression is controlled. We hope that we and other researchers may be able to test this process in humans and then develop new treatments for preventing visual disorders or cure colour blindness and vision loss diseases."