2. In a mixing bowl, combine olive oil, chili powder, cumin, garlic powder, salt, and black pepper.
3. Brush the Mahi Mahi fillets with the marinade mixture.
4. Grill the fish for about 4-5 minutes on each side, until it flakes easily with a fork.
5. Warm the tortillas on the grill for about 30 seconds on each side.
6. Assemble the tacos by placing grilled fish in each tortilla, then topping with shredded cabbage, avocado slices, chopped cilantro, and a squeeze of lime.