Gather all ingredients and pat the cod fillets dry.
In a medium bowl, whisk together beer, flour, egg, garlic powder, salt, and black pepper until smooth.
Add cod fillets to the batter and gently coat completely.
In a separate bowl, mix crushed cornflake crumbs with Cajun seasoning.
Remove cod from the batter, allowing excess to drip off.
Press each fillet into the cornflake mixture, coating all sides thoroughly.
Heat oil in a large skillet or deep fryer to 365°F (185°C).
Carefully place coated fillets into the hot oil.
Fry until golden brown and the fish flakes easily with a fork.
Remove and drain on a paper towel-lined plate.
Serve immediately while hot and crispy.
