Within the family Anablepidae, there is a genus Anableps which are known as four-eyed fish. They are found in Central and South America in fresh or brackish waters. These fish are live bearers and interestingly they exhibit a “sidedness”. Males that are left-handed may only mate with females that are right-handed.
Now the fish do not have four eyes exactly, but in both eyes they can see above and below water simultaneously. This is a good super power to have when you spend most of your time on the surface foraging insects.
Photo Credit: Paul Zahl/National Geographic
The retina is specialized so that half receives light from the aquatic environment and the other from the aerial environment. Recent research found that the dorsal and ventral retina have differential gene expression. Click here for a link to the article to learn more.
