Hi Israel,
I only just saw your original post and your more recent ones.
I too have had discus with what looks like a shredded fin. The most pronounced was my Marlboro Red. He had it by the time he was about 5 months old. I just finally accepted it as normal for him. It didn't affect his offspring. It is also possible that any who inherited the mutation were ones that I culled so I never noticed it.
All of the now adult offspring who live near enough to me for me to visit them have normal pectoral fins.
I know that doesn't help with your beautiful calico with the splayed pectoral fin, but hopefully you can now breathe a little easier and know that it's a natural mutation and not worry about it or try to cure it.