- Fish skin contains collagen, a protein that is used in, for example, cosmetics to increase skin elasticity and strength. Moreover, fish skin contains many minerals such as protein, unsaturated fatty acids, sulfur, choline, lecithin and calcium. + Choline enhances memory. + Lecithin has the effect of protecting the liver, promoting the nervous system and developing the brain. + Unsaturated fatty acids are effective in the prevention and treatment of atherosclerosis, high cholesterol, high blood pressure and cardiovascular disease.