I use a cast iron dutch oven on the stove top, digital thermometer in the oil making sure it isn't touching the bottom and heat till 350, maybe a little higher if the fish is coming straight from the fridge. Dropping cold fish, and especially frozen fries, will drop the temp, so I may crank up the heat as I drop the food in and lower it again as it stabilizes back to 350. I don't use a timer, just cook til GBD (Golden Brown and Delicious).

I prefer Peanut oil, but have switched to Canola oil now for healthier cooking (still fried, but every little bit helps). I also have used shortening (both regular and pure vegetable) and vegetable oil too.

What oil do you guys like to use?

As a matter of fact, my girlfriend (who beats me) is mixing some Hush Puppy batter right now and I am getting ready to fry yesterdays catch.