The nutrient that imparts the pink flesh color is astaxanthin, that salmon ingest when they feed on other marine organisms, such as krill and small shrimp. It has become a running joke that when a male wears clothing that is pale pink (usually bought by a female loved one) to emphatically insist "It's not pink, it's salmon!"
This is the color called salmon in Crayola crayons. This color was introduced by Crayola in 1949. See the List of Crayola crayon colors. The color is also one of the official colors of Alpha Kappa Alpha Sorority, Incorporated.