Battered Cod Fish Tacos

Name: Battered Cod Fish Tacos
Ingredients: vegetable oil (for frying); 1 pound fresh cod; 1 cup all-purpose flour; 1 teaspoon baking powder; 1 teaspoon ground mustard; 1 teaspoon garlic powder; 1 teaspoon onion powder; 1/2 teaspoon salt; 1/4 teaspoon black pepper; 1 cup root beer; 4 roma tomatoes (diced); 1/2 white onion (minced); 1/4 fresh cilantro leaves (chopped); 2 avocados (diced); 2 limes (juiced); 1 teaspoon salt; 2 cups shredded green cabbage; 1/2 cup red wine vinegar; 1/4 teaspoon salt; 16 corn tortillas