I used to catch croppie by the thousands, and eat them by the hundreds about 10 years ago. That is an excellent eating fish, but very delicate and low in fat. I would fillet them, skin them, and remove the rib cage and the pesky vertical bones at a rate of about 2 fish per minute.
Deep frying them is the way to go. I would dry the fillets bone dry, then spinkle with garlic salt and pepper, then dust with minimal flour. Once the peanut oil reached 375degF I would start a timer at 1minute and 45seconds and drop the fillets in largest to smallest. There was never much of any oil remaining on the fillets when I pulled them out since the surface skinned over hard.
As for catfish Shannow, leave them rippin' in the oil for about 10 minutes with corn meal batter if they are the farm bred variety. Natives can take a minute or two less. If tuna is chicken of the sea, catfish is chicken of the lake. Steer clear of the lungfish!