- a small, surface-swimming fish, Anableps anableps, inhabiting shallow, muddy streams of Mexico and Central America, having each eye divided, with the upper half adapted for seeing in air and the lower half for seeing in water.
- either of two viviparous tropical American freshwater cyprinodont fishes, Anableps anableps or A. microlepis, that swim at the surface of the water and have half of each eye specialized for seeing in air, the other half for seeing in water
