Mahi-mahi supplies many micronutrients and vitamins that are part of a healthy diet. It's one of the leanest fish you can buy, which means these fillets are relatively light and low in fat. They have plenty of protein, making them a great choice if you're eating a high-protein, low-fat diet. Because mahi-mahi is one of the less oily fish you can eat, it doesn't supply quite as many omega-3 fatty acids as fish such as salmon do. However, it does provide some of this healthy fat.