Cave-dwelling fish, which may belong to one of several quite unrelated groups, independently adapted to life in underground waters. Cavefish have in common a tendency to blindness and atrophy of the eye, enhanced touch-sensitive organs in the skin, and loss of pigment.

The Kentucky blindfish Amblyopsis spelaea, which lives underground in limestone caves, has eyes that are vestigial and beneath the skin, and a colourless body. The Mexican cave characin is a blind, colourless form of Astyanax fasciatus found in surface rivers of Mexico.