Drizzle the olive oil over the fillets, and apply salt and pepper to taste.
In a small bowl, combine the paprika, chili powder and cumin. Mix to combine.
Sprinkle the herb mixture over the fillets, and rub it in with your hands on both sides.
Bake the fillets for 20 minutes.
While the fish is baking, prepare the filling for your tacos. Shred the red cabbage, chop the tomatoes and avocado, and crumble the queso fresco cheese.
To assemble your fish tacos, cut the fish fillets into bite sized pieces. Place a large leaf of lettuce down, and top it with some shredded cabbage, 1 tbsp of chopped tomato, some chopped avocado, some of the fish pieces, and a dab of sour cream.