It's amazing how adaptable fish can be that are missing fins. I have caught bluegills with their entire caudal fin missing probably from musky attacks in a local lake. Everything healed up nice but there was no tail!

Speaking of fins I have seen some interesting anomolies regarding fish fins as a taxidermist. I once took a crappie in which the pelvic fins were all one conjoined fin like a hand held fan. I also took a walleye in once that never grew one of it's pelvic fins. It wasn't cut off etc. it just never grew one and had scales where the fin should have been.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.