I know people get all caught up in how they cook their fish but I use the KISS method - Keep It Simple Stupid.

My fillets are generally frozen and thawed before frying up. They stay in a cold water bath - usually the thawed/frozen water. If for some reason, I'm cooking fish just caught, I will rinse them really good with very cold water.

My coating is yellow corn meal, salt & pepper. Put that mixture in a ziploc baggie (been doing it that way for years) or one of those shaker basket things from BPS if you wanna be fancy). That's it. Take your wet fillets and coat them with the corn meal mixture. Drop them in peanut oil that is slightly over 350 degrees. Slightly over because the cold fillets will cool it off a little. Careful going over 350 degrees with cooking oils.

When they float, they are done. Break one open to confirm.

My other coating mixture and method is:
corn meal, salt, pepper & crushed red pepper (purchased at asian food markets - don't know why this is better. It just is.)
I fill up a bowl with sriracha hot sauce and run my fillets through that to drench them in the hot sauce. Then I coat them with the pepper/corn meal mixture. Cook in the oil. This is a spicy fish.

I do at least 1 300+ fillet fish fry every year and have never had a complaint....yet.

I dry out my fillets with paper towels completely before battering them. You would think it wouldn't stick as well, but I think it does better and your not frying any extra moisture to separate the cornmeal from the fish. Let a match float on your oil. When it ignites, the oil is ready to cook.

Drop a popcorn kernal in the oil and if it pops, the oil is ready.

Haha! I hope no one on here is stupid enough to actually do that!!!