If you look up cauliflower disease, you find it has never been reported in catfish.It usually cures itself in fish that are afflicted, and since it is viral, there aren't any medicines for it. My experience with Erthromycin is that it is useless for anything but blue green algae.
Yes, that's what I saw as well. Which seemed strange but I saw two references to this flicking through google.
Edit - to catfish not getting it I mean