Lay shrimp and fish in a shallow dish. Cut limes in half and squeeze juice over shrimp and fish.
Sprinkle Cajun seasoning, garlic powder, and salt/pepper over shrimp and fish.
Heat a medium skillet to medium heat and add oil. Cook shrimp and fish until done and set aside.
Arrange tortillas on a flat surface and add the following to each: 1 romaine lettuce leaf, shredded red cabbage, approximately 1-2 tbsp. of guacamole, 1-2 tbsp. of sour cream, and tomatoes.
Add 1 piece of fish and evenly distribute shrimp on each taco. Sprinkle cilantro on top and add sliced limes for garnish.
Nutritional Information (1 taco): Calories 355, Carbohydrate 24g, Fat 14g, Protein 35g, Saturated Fat 5g, Fiber 3g, Sugars 2g