Fish oil is the oil from rendering (cooking down) whole fish or cannery waste. (AAFCO, 2003) Cannery waste can contain fish that are damaged, defective, or contain material produced during, or left over from, the manufacturing process. Many pet food manufacturers use this generic type of oil, which is has low amounts of nutrients and health benefits. Good quality fish oil will have been properly processed in a low heat processing as to not harm the omega 3 fatty acids, which are excellent for skin and coat, as well as be free from harmful contaminants such as heavy metals and PCB’s. The best oils also specify the source of the oil, such as salmon oil or herring oil.