In a small bowl, whisk taco seasoning, garlic powder, salt and pepper.
In a large rimmed baking dish, add fish, drizzle with oil and rub it around. Sprinkle with mixed seasoning on both sides and set aside.
Meanwhile, chop and add mango, red onion, cilantro, lime juice, jalapeno and salt to a medium bowl. Stir and set aside.
Preheat grill on medium high heat and oil grill grates with oiled paper towel. Grill fish untouched while covered until white and opaque on the bottom, about 4 minutes. Carefully flip on the other side and cook another 4 minutes.
Warm up tortillas on the grill or microwave and keep warm under the towel.
To assemble a taco, flake fish with a fork, place desired amount in a warm tortilla and top with mango salsa. If you would like to make white sauce (crema), I included recipe below in notes.
Notes
Store: Store grilled fish leftovers in an airtight container in the refrigerator for up to 3 days. Mango salsa can also be stored for up to 24 hours. Reheat in a skillet with a splash of water or oil on low heat and cover until heated through.
Crema recipe (optional):I think mango salsa makes grilled fish tacos super juicy and flavorful. But if you would like to drizzle white sauce as well, here is the one I use for my regular fish tacos.