OILY FISH NUTRITION Oily fish include herring, salmon, sardines, sprats, trout, and mackerel. They are high in Omega 3 fatty acids and a good source of vitamin D. Note that fresh and canned tuna do not count as oily fish. A few of the health benefits of oily fish are the following: they help protect against heart disease, have neuroprotective properties, they protect joints, help support good mental health and help to reduce the risk of certain cancers. Health experts recommend eating fish at least once or twice each week. The best methods of preparing fish are: sous vide, microwaving, baking, steaming, and poaching.