Most fish are rich in long-chain omega-3 fatty acids.
These molecules are fundamental to growth, and particularly the development of nerve cells and the retina. They reduce cholesterol, and their anti-inflammatory properties might be useful in the management of inflammatory and autoimmune diseases such as rheumatoid arthritis and multiple sclerosis.
It seems that eating fish plays an important role in preventing hormone-sensitive cancers like breast, prostate and colon. However, not all fish have the same concentration of omega-3s.
Wild fish have higher concentrations than farmed. The following fish, mollusks and crustaceans are high in fatty acids and low in mercury: anchovies, poor cod, cod, herring, mackerel, Alaska pollock (commonly ground up to produce surimi, the Japanese-invented fish paste now used around the world to make imitation seafood products such as crab sticks), salmon, European smelt, whitefish, prawns, shrimp, clams, mussels and oysters.