Omega-3 Fish oil is one of the most commonly consumed dietary supplements. It's rich in omega-3 fatty acids, which are very important for health. It usually comes from oily fish, such as Sardine, herring, tuna, anchovies, and mackerel. Around 30% of fish oil is made up of omega-3s, while the remaining 70% is made up of other fats. The main omega-3s in fish oil are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), EPA and DHA have many more health benefits.