happed to me when 1 oscar stripped the other ones tale to the flesh luckely it grew completely back in a couple of months. Best of luck with your oscar I really hope he gets back to 100%
I had a similar experience. My pacu chewed the nose off of rather large fla/spotted gar of mine, bone and all! And this was a VERY well fed baby red belly pacu around 8 inches! good luck and hope your oscar comes around.