Fish oils offer high concentrations of polyunsaturated fats called omega 3 fatty acids. While all fish contain these fats, deep sea cold water fish: sardine, anchovy and tuna are particularly rich sources because of their primary food source: plankton is packed with omega 3 fatty acids. The predominant essential fatty acids of omega 3 are Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA).