Ooh that is a good question! Well, apparently light leaving water refracts on the surface of water. This means a fish in a river will look closer to the surface, than it really is, to a person looking in from the side...

SOURCE: https://www.sciencelearn.org.nz/images/59-refraction-and-spearfishing#:~:text=Light%20coming%20from%20the%20fish,real%20position%20of%20the%20fish.