I've had it before as a kid and liked it. This is not my recipe though, I found it on cooks.com, people share a lot of good recipes on there.
Roll filets in dry pancake mix and let stand 20 minutes.
BATTER: Start with one cup pancake mix. Add 1 egg. Mix in slowly about 8 ounces of 7-UP or until batter is thin. Preheat deep fryer to 365-400 degrees. Dip filets in batter and fry 3 or 4 minutes.