Salmon is a very popular fish, being large and high in omega-3 fatty acids. Canned salmon is high in calcium because the bones have been softened and are eaten with the meat. Salmon is particularly popular in the American Jewish community. The eggs are sometimes eaten as a caviar substitute.
The line-caught variety is especially prized and expensive. Much like flamingos, wild salmon gain their pink or red color from the krill (small shrimp-like animals) that they eat. Color differences indicate food source differences. Farm-raised salmon are artificially colored by feeding them a dye that tends to remain in flesh. The dye has been shown to remain in humans, including the retina, which can be damaging to eyesight. Farm-raised salmon taste somewhat like corn, likely due to the feed being used. Farm-raised salmon can be recognized by the wider fat-filled or goo-filled gaps between the flakes of meat.
When purchasing fish, freshness is important. The fish should not have a fishy smell, which actually comes from bacteria decomposing the fish. If purchasing whole fish, the eyes should be clear. Frozen-at-sea fish are often the freshest choice available.
Trout may be substituted for salmon.