Four-eyed Fish

Range: Southern Mexico to northern South America
Habitat: Swamps; shallow, muddy streams
Conservation Status: Not listed by IUCN
Scientific Name: Anableps sp.

This swamp-dweller gives new meaning to the term "four eyes."

Each of the fish's two eyes is divided by a horizontal band, essentially creating four eyes. The upper portions see above the water and the lower portions see below…at the same time! This special ability lets the fish keep an eye out for food or foes, wherever they may be -- a handy adaptation for life at the water's surface.

Four-eyed fish are unusual in another way. Both males and females have sex organs that are turned either to the right or to the left. A "right" female can only mate with a "left" male, and vice versa. This feature is shared with only a few other fish species.