Why do fish seen to change position as you look at them from different view points?

Fish appear to change position due to a phenomenon called perspective and the refraction of light. When viewed from different angles, the way light bends as it passes through water can alter the perceived location of the fish. Additionally, the three-dimensional structure of the fish and its environment can create an illusion of movement or position change as you shift your viewpoint. This effect can be enhanced by the fish's own movements and the surrounding water currents.