Fishes are an excellent source of high quality protein. The biological value of fish protein is 80. They are low in fat particularly cholesterol & saturated fats. Besides they are especially rich in omega-3 fatty acids, beneficial to the heart. Being poor in carbohydrates they are not good sources of energy.
They are rich in calcium, particularly small fishes eaten with bones. Canned fishes are very rich in calcium since during processing they become soft to be eaten. Additionally marine fishes are good sources of iodine. Being low in sodium they are sufficiently rich in potassium. Fish liver oils are excellent sources of fat soluble vitamins. Rohu (Indian fish) contains Vitamin C. They are also good sources of vitamin D and niacin.