If using frozen catfish, thaw fish first by rinsing in cold water in a colander or allowing to thaw in the refrigerator
Use a heavy-duty skillet (cast-iron) or Dutch oven
The amount of oil depends upon the size of your skillet; you want about 2" inches of oil
If the oil starts to smoke, turn the heat down and remove the skillet from the burner for a few minutes. After the heat has been reduced, put the skillet back on the burner. Keep an eye on the oil.
Do not move the catfish fillets for the first 3-minutes; if you do, the coating will fall apart. Just stand there and watch...and wait
When flipping the fillets, use tongs or a spider
Your second batch of fillets will be darker than the first; that's because they're being cooked in oil that's already been used. If this really bugs you, throw out the first batch of oil and start over.
Use a thermometer; internal temperature should be 145ºF
Don't have buttermilk?Make your own! Add 1 tablespoon fresh lemon juice to 1 cup of plain milk. Stir it and let it sit for a few minutes at room temperature. Now you have buttermilk!