Invertebrates and fish

This the Arizona state fish

This is an endangerd species

Additional information about this this fish says that the pigmentation and eyes have degenerated over generations due to the high energy cost of maintaining eye tissues which they do not need in the dark cave system. It stated that the vertebrate retina is one of the most energy expensive tissues, with an metabolism's passing that of even the brain. To compensate for the loss of eyes, this fish has evolved a larger jaw, a higher number of taste buds and higher number of teeth in order to be more efficient finding food.