I recently had a angel and a damsel get into a bad fight. The Damsel has about 4 spots where it looks like some scales will fall off and he is missing part of his tail. Will things like this heal?
If given time they may. But I would get it out.
Another fight will probly happen again and make things worse. Once a fish is wounded by another fish, it's just a matter of time before it happens again.
The folks in the disease & treatment forum could help with injury recovery far better than I could. They could heal I'd think....but for certain I would seperate them at least. If they stay in the same system there will be futher damage and death. Not a good thing to deal with in my opinion. I hope they survive....