Pat the fish dry with paper towels, then season.
Put the flour in a shallow bowl and dust all of each filet with the flour.
In a heavy bottomed pot, add 1” of vegetable oil and heat until the oil reaches 360 degrees F.
Prepare wire rack by lining with 2 sheets of paper towels.
Fry the catfish in batches and drain on the paper towel lined rack.
Add the bell pepper, onions, lemon zest and juice, vinegar, sugar, bay and thyme to a bowl and stir to combine.
Salt and pepper to taste.
Place the warm fried fish in a shallow non-reactive container such as a glass baking dish and pour the vegetables and marinade over the top of the fish, making sure to cover it evenly with the onion and bell pepper mixture.
Refrigerate overnight and serve at room temperature with a salad or crusty bread.