Fish-eye view. Illustration showing how refraction of light allows a fish to see a wide-angled view above the surface of the water. Light travels at different velocities in different media, and as a light ray passes from one medium to another it appears to bend. As light travels more slowly in water than in air, light bends and the images of objects above the surface are displaced into the fish's field of vision, within a cone of 98 degrees. Outside this angle (twice the critical angle for water), light from objects inside the pond is reflected back from the surface.