They provide about 1 gram of omega
fatty acids in about 3.5 ounces of fish
. Fish oil
supplements are usually made from mackerel, herring, tuna, halibut, salmon, cod liver, whale blubber, or seal blubber. Fish oil supplements often contain small amounts of vitamin E to prevent spoilage. They might also be combined with calcium, iron, or vitamins A, B1, B2, B3, C, or D.
Fish oil is used for a wide range of conditions.