Hmmmmm......This is a tough one. I guess it depends on what kind of fish cleaning you want to do. If you're filleting the fish, a very thin blade like on a Spyderco Catherman is essential. Unfortunately, I can't think of a folding fillet knife that would be usable priest.
Now if you're simply gutting and cutting off the head of your fish, options begin to open up. First off is the venerable Buck 110. Those brass bolsters, mixed with the somewhat heavy weight, could do some damage to a fish's noggin. As far as self-defense goes, people have fought off bears with Buck 110s!!!
Personally, I'd do a fixed blade in the great outdoors. If you like carbon steel, a Marbles CampCraft would do all of what you need without breaking your budget. You have to watch for rust, but it's scary sharp, sharpens easily, and really holds an edge. The grind and blade thickness are just right for gutting fish, ans it has nice butt cap for crackin' skulls.
Something must be wrong with me. With all of the whizz-bang new fangled gadgets out there, my recommendations are probably the same as my dad would have gotten 40 years ago.
