In a large pan over high heat, heat oil until hot.
In a large non-reactive pan, soak fillets in beer, lemon juice, and lime juice, about 5 minutes.
On a large plate, spread out white corn meal.
Remove fillet, one at a time, and coat in corn meal.
Place in hot oil. Cook for 5 to 6 minutes per side or until golden brown. Turn Once!)
Repeat cooking process until all fish are cooked.
Drain fillets on a paper towel. Let rest for 5 minutes before serving.
In a medium bowl, mix mayo, onion, pickle, and lemon juice.
Stir to incorporate. Serve with catfish.