8 to 10 Slices,Omega-3 fatty acids are found in every kind of fish, but they are especially high in fatty, oily fish. Because many of these fish live in cold waters, the meat has a high fat content and is rich in fatty acids healthy polyunsaturated fats. But, they're low in saturated fat and high in protein. These fish are also good sources of vitamin D, selenium, phosphorus, iron, and iodine.