Fish oil is oil derived from the tissues of oily fish. Fish oils contain the Omega-3 fatty acids, EPA and DHA, precursors of certain eicosanoids that are known to reduce inflammation in the body, and have other health benefits.

The fish used as sources do not actually produce omega-3 fatty acids, but instead accumulate them by consuming either microalgae or prey fish that have accumulated Omega-3 fatty acids, together with a high quantity of antioxidants such as iodide and selenium, from microalgae, where these antioxidants are able to protect the fragile polyunsaturated lipids from peroxidation.

Fish oil is used as a component in aquaculture feed. More than 50 percent of the world’s fish oil used in aquaculture feed is fed to farmed salmon.