Fish oil can have benefits for eye, heart, liver, and brain health. The supplement is a source of omega-3 fatty acids, which decrease inflammation. Fish oil is extracted from oily fish like herring, tuna, anchovies, and mackerel. It contains omega-3 fatty acids, which have many health benefits. About 30% of fish oil is omega-3s, along with. That’s because fish oil supplements are a pill form of omega-3 fatty acids, which have been studied for decades and have proven benefits for heart health. Find the best deals on Costco's great selection of fish oils and Omega-3 products. Shop online at Costco.com today! Fish oil is oil derived from the tissues of oily fish. Fish Oil capsules contain omega-3 polyunsaturated fatty acids. Omega-3 polyunsaturated fatty acids are found in oils from certain types of fish, vegetables, and other plant sources. These fatty acids are not made by the body and must be consumed in the diet. Fish oil contains two omega-3s called docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Dietary sources of DHA and EPA are fatty fish, such as salmon, mackerel and trout, and shellfish, such as mussels, oysters and crabs. The latest science on fish oil supplements, including their benefits, risks, and whether to take or skip it. Learn about the best Omega-3 fish oil supplements containing EPA and DHA essential fats for better heart and joint health. Fish Oil Benefits: Find out what the research says about fish oil, who should have it, and how it may affect your health. Know the nutritional benefits and pros and cons of fish oil.