My boyfriend and I ate at a Thai restaurant tonight that had a huge fish tank. While we enjoyed our shrimp pad thai (ironic, isn't it?) I noticed that the fish kept bumping into the walls of the tank. Is this because their eyes are on the sides of their head? Can they see in front of them with their eye placement? Or are they just stupid?
Taken from an excellent article here:
Essentially, the fish is nearsighted when looking forward at a food item near its mouth, but is farsighted to the side and is able to locate possible predators lurking in the distance. But because most fish have eyes situated on the sides of the heads, their ability to judge distance is not as acute as it is with terrestrial vertebrates. (As humans our eyes look forward so we have binocular vision and are able to judge distances fairly accurately). And because their eyes are situated on the sides of their heads, fish almost have a three hundred and sixty degree view of their world. Of course, fish with broad heads or large tails have blind spots they must compensate for by sweeping their heads from side to side.