I've been thinking about doing this for a long time and finally tried it this week. I cooked a whole mutton snapper(about 7 pounds) in a turkey fryer. It was awesome and i can't wait to do it again. Next time I'll take some pictures as this thing looked awesome when it was done and it tasted even better than it looked.
I started out with a fresh mutton we caught the day before. Scaled, gilled, gutted, and the dorsal and anal fins trimmed off. I made cuts every inch or so down to the bone across the fish from top to bottom. I dusted the fish with a mix of whole wheat flour, old bay, creole seasoning, everglades seasoning, and pepper. I ran a coat hanger through the eyes and dropped it in the turkey fryer heated to about 300 degrees. I didn't know how long it would take so I just kind of kept an eye on it and pulled it out and checked it a few times. I think it wound up taking somewhere around 25 minutes.
It was really, really, good. I've always been a fan of smaller whole fried fish like yellowtail, but had never tried a bigger fish like a mutton. The skin was so crispy. The pec fins and tail turned into something like crispy fish bacon. I served it with melted butter, spinach, salad, and rice. I've got the turkey fryer out for thanksgiving and plan on trying again this week as long as one of the customers let me keep a nice snapper to cook.
I'm going to take some pictures and maybe even take some video next time.