Salmon is the common name for several species of fish of the family Salmonidae. Several other fish species in the same family are called trout, the difference is that salmon lead a migratory life. Salmon live in both the Atlantic and Pacific Oceans, as well as in the Great Lakes (approximately a dozen species of the genus Oncorhynchus live in the Great Lakes). Salmon are anadromous, meaning that they migrate between freshwater and saltwater habitats, while trout remain in freshwater for their entire life cycle. Salmon are born in fresh water, migrate to the ocean to mature, then return to freshwater by swimming from the ocean in rivers upstream to reproduce. There are some rare species of salmon that can now survive only in fresh water habitats due to the domestication of those species.
Salmon is a popular food both because of its delicious taste and versatility and its high nutritional value. Consuming salmon is considered to be healthy because of the fish's high protein, high Omega-3 fatty acids and high vitamin D content. Salmon flesh is generally orange to red in color, although there are some examples of white fleshed wild salmon. The orange color of salmon results from carotenoid pigments that wild salmon get from eating krill and other tiny shellfish.