The astyanax mexicanus, a blind cave fish,was discovered by reasearchers to have a smaller brain than sighted fish. their explenation for it was that the fish got rid of its eyes because they used more enery than needed in the dark cave environment in which it lived, but the writer of this artical and me aren't so sure that's exactly true. THis artical then goes on to speak about how there would be three possible places that enery could be the cause for the lack of eyes, in developement of the embryo, in keeping them as an adult, and finally when "turning them on". each of these steps needs energy and the fish would seem to have enough for every step except the last, "turning them on", because this requires a source of energy outside the body
