Fish fillets is high in protein. Can be easily digested It is also rich in various minerals, such as mineral iodine. Most often found in marine fishes. Iodine is a mineral that helps in the synthesis of thyroid hormones. Thyroid hormones are importance. Is oxidation control inside cells and affects the brain of the fetus. In addition, fish fillets also contain various mineral that are beneficial to the body, such as calcium, sodium, potassium, magnesium, copper, zinc, manganese and iron. The various minerals these are minerals that play a role in the metabolic processes of the body. But, if get these minerals in an excessive higher concentration the body of needs cause toxicity. Be the cause of the body disorders, cause of disability. Currently, industries such as agriculture, food, a lot of occur. In order to manufacture products given sufficient demand of human. Growth of the industry As a result, the dumping of waste from the production in industrial factory such as waste water, solid waste, chemicals into the soil, water, air, and some may have flowed into the sea. Particularly heavy metals such as lead, cobalt, cadmium, arsenic. Have an effect on marine animals such as fish, shellfish are contaminated with toxic from waste. May be remain in the animals. When consumers eat marine animals containing residues prolonged contact, may affect the body. Therefore, to reduce toxins in fish fillets. Must be cooked through the process of frying, steaming, boiling, baking and grilling to reduce residue prior to be consumed. Which found that Iodine contents in fish fillets each type are different. Fish fillets grilled to have iodine content highest. But fish fillets cooked by baking, steaming, and boiling will have calcium content, sodium, potassium and magnesium. Remaining in fish fillets rather than frying. The cooking by frying, keep the concentration of arsenic and cadmium increased significantly. But the fish through the oven has dropped significantly. A decrease in the concentration of arsenic and cadmium, depending on condition such as temperature and time. Therefore is it possible that the choice of how cooked the right amount assist preserve various minerals. Useful in fish fillets remain and reduce the concentration of heavy metals in fish. In order to safe to consume.