Tortillas: Heat in a dry seasoned skillet over medium heat. Add tortilla and cook until its golden and starts to brown in spots, about 20 seconds, then flip and cook until other side is golden. The tortilla should still be soft and pliable, not crispy.
Fish: Mix all the batter ingredients together in a large bowl. Start with half of a can of soda and add to get to the consistency of pancake batter.
Slice fish into strips approximately 4” long. Pat fish very dry and add all of the fish to the batter and gently stir to coat.
Fill a 12-inch pan with about 2 inch deep oil and heat to 375 degrees F.
Working in batches, fry fish until golden, flipping halfway through. Place on paper bag or paper towels.
Assemble: Add fish to tortillas and top with Jalapeno Aioli, Cotija cheese, freshly squeezed lemon juice and avocado.