Fish meal raw materials and nutritional composition fish is an important source of nutrition. It has high protein content, superior fat composition and special nutritional value. The chemical composition of different kinds of fish, different organs and tissues varies greatly (as shown in Table 1). Taking the chemical composition of black backed fresh fish and COD as an example, the protein content of scales, skins and eggs is higher, while the protein quality of eggs is the best. Table 1 chemical composition of different kinds of fish, different organs