Cut the fish into strips about 3-4 inches long. Pat them dry with a paper towel to help the batter stick.
In a large mixing bowl, whisk together the flour, cornstarch, baking powder, salt, garlic powder, and smoked paprika.
Gradually add the cold beer, whisking continuously, until the batter is smooth and has a pancake batter consistency.
Heat about 1 inch of vegetable oil in a large skillet over medium-high heat (about 350°F).
Dip each fish strip into the batter, allowing excess to drip off, then carefully place it into the hot oil.
Fry for about 3-4 minutes per side or until golden brown and crispy.
Transfer the cooked fish to a paper towel-lined plate to drain excess oil.