Why do salmon turn red?
Salmon flesh is red due to their diet. Salmon gain 99% or more of their body mass in the ocean and the food they eat in the ocean is high in carotenoids (the same pigment that gives carrots color). These pigments are stored in their flesh. As salmon approach their spawning grounds they begin to absorb their scales. The carotenoid pigments in their flesh are transferred to the skin and eggs. By the time they spawn, their flesh is truly white because of all the carotenoids have been moved out of the flesh. The red skin makes them more visible and may signal their readiness to spawn. The pigments may also help the fish absorb oxygen from the water.