Blend together the avocado cilantro sauce ingredients, set aside.
Bring a large pot of vegetable oil to 350F.
Whisk together beer, flour, salt, egg, and baking powder until a smooth batter forms.
Coat the cod in the batter and lower into the oil.
Fry until golden brown and the fish is cooked (about 5 minutes).
Assemble cod into tortillas and drizzle avocado sauce over. Top with cabbage, radish and cilantro.