I once read an article (I can't find it now to link) that said fish have ten times the number of endorphins as humans and thus don't feel physical pain. Endorphins don't suppress all feeling, just the electromagnetic signal the body uses to convey pain to the brain. IF that article was correct, your fish wouldn't feel the injuries it has as long as it can function normally.
I have a spotted Raphael catfish that I have had for about 10 years, 5 ish years ago, I redid some decor in the tank he was in and he wad up inside a rock and sat in the kitchen sink, for a day and a half while the rock dried out. When I went to put the rock away, the catfish fell out, dry, yet still breathing. I put him back in the tank and over the course of the next month or so, the entire back half of his body died, fell off, and regrew in its entirety. He is now about 7" long. Its possible for all of it to regrow. Just use your discretion.
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