The raw materials for making fish oil preparations are commonly found in mackerel, herring, tuna, halibut, salmon, cod liver, whale fat, seal oil, etc. Generally, a small amount of vitamin E is added to play an antioxidant role. Broadly speaking, fish oil refers to the fat of fish, including fish liver oil. However, the main functional components of fish oil are DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), which have effects on regulating blood lipids. The main functional components of fish liver oil are vitamin A and vitamin D, which are mainly used to prevent and treat vitamin A and vitamin D deficiency.