Fish Eyes
In addition to a running discussion of fish ears, I want to talk about fish eyes, too. There are a number of questions that keep coming up relative to fish vision that tell me the pool of misconceptions is still deep, dark, and slow moving. Here’s the much compressed lowdown on fish vision. These items will be expanded as we go forward.
1. Fish see in color.
2. Fish vision is not as detailed as ours (ours is not as detailed as an eagle’s).
3. Fish can move their eyes (just like we can move ours) and they can move them independently (we have a very hard time doing this).
4. If you can see the fish, it can see you.
5. More to come.
Let’s start the whole discussion with a look at the positioning of the fish’s eyes. Humans, lions, tigers, and bears, oh my, have their eyes facing forward because they are at the top of the food chain—predators, all of them. The eyes in the front give them excellent binocular vision (ours is about 90 degrees) so they can better see their prey as they race after it. Fish, gnus, deer, cows, and the like have their eyes at the sides of the head so that can keep an eye on the predator behind them. This restricts their field of forward binocular vision to about 30 degrees.
Conclusion: You’re a predator, start acting like one because the fish is prey, and they most certainly act like it.
The fish's eyes are at the sides of the head "the better to see you mine otter." Their field of forward, binocular vision is only about 30 degrees.