1. Add Florida Grapefruit, Florida Orange, onions, tomato, bell pepper, jalapeño, cilantro and garlic in a bowl and stir to combine. Cover and refrigerate until ready to use.
2. Season mahi mahi with salt and pepper. Heat a grill or grill pan to medium-high heat.
3. Grill mahi mahi for 5 to 6 minutes, turning once after 3 minutes. Do not overcook the fish. Place fish on a serving plate and top with Fresh Grapefruit Salsa.