Place all ingredients into a mixing bowl.
Whisk together and set aside until ready to use.
Preheat oil to 350˚F in a wide skillet with tall sides.
Season cod pieces with salt and pepper.
Place flour, cornstarch, salt, and pepper together in a mixing bowl.
Whisk dry ingredients together until smooth.
Add beer to flour mixture and whisk together until smooth.
Dip fish into batter until fully submerged, a couple pieces at a time.
Shake excess batter off each piece and carefully drop them into the hot oil. Fry fish for 4 to 5 minutes or until golden brown. Remove from oil and place onto a baking sheet lined with a cooling rack . Season with salt and pepper.
Spread a couple spoonfuls of baja sauce in the center of each tortilla. Top with a couple pieces of fried fish. Top each taco with a small handful of shredded cabbage and a couple spoonfuls of pico de gallo. Serve with lime wedges on the side.
