Combine flour, pepper, salt and the parsley in a medium bowl.
Slowly pour in the beer little by little, stirring constantly to break up the clumps, until you get a smooth batter.
Preheat olive oil in a pan over medium heat.
Season the fish with salt and pepper. Dip the fish in the beer batter and completely cover. Remove from batter and transfer immediately to the hot pan. Fry oil until they´re brown. Once browned, transfer fried fish to paper towels to drain off excess oil.
Heat the tortillas and fill them with the fried fish.
Serve the tacos with ketchup and mayonnaise and any of your other favorite taco fixings.