Hi everyone, sorry that my first post here is asking for help but I'm at a loss for how to help this guy. He's very energetic and has been this way for a while now, so I'm hopeful someone will know something in time to help him. There's a fairly long chain of events that I will try to make concise. The start of his chain of illness/injury was a columnaris pandemic that rolled in while my wife and I were (of course) out of town visiting family for a week. We were able to treat them successfully with a mix of furan-2 and kanaplex but we lost about half of our goldfish to it as some died before we returned and some were too far gone to help. One of our other goldfish had been nipping at the white patches growing on the oranda's head bubbles and did a fair amount of damage to them before we saw and separated him. He has now been in quarantine for about a month, we continued through two full courses of furan-2 and kanaplex and took care of the columnaris but our oranda took on these black growth-like things on his head. I have been unable to find any information on any infection, illness, or fungal growth that looks like this. The only thing that seems close is some people have described the healing process as looking somewhat like this but it seems to be spreading to areas that weren't damaged, and now his fins also have picked up some black at the ends. We started on a dose of general cure but it did not seem to be helping so we did not complete the full course. Currently we are only treating him with aquarium salts as we are at a loss of what to try. We have nearly every fish medication known to man in stock, and live in close proximity to several well-stocked stores if we need something we don't have. Does anyone have any idea what this could be? Or what a good course of treatment would be? Would love for this guy to get better, I feel bad keeping him away for his friends so long and I don't want him to die in quarantine.