something is on my Yellow tangs tail

[thincat]

Well I have a buddy with a 75g that's been running,
I may just let him babysit for me. Cus I agree that he doesn't need to be in the 24g. I figured it was better than the 10g, but still not good. I understand that. I really want the best for the tang

From what I read about the disease is that it falls off and then turns into a virus factory which burst into a lot more viruses that infect fish of like type. I would wait until it falls off before giving the disease to your friends tank.
Another thing to worry about is that this could transfer into humans so wear gloves if you plan to handle the fish.

Lymphocystis Disease of Fishes, by Dr. Adrian Lawler