u may have treated too early. do you have an empty running tank available? it may be a good idea to separate him. it's hard to give a diagnosis w/out more info, but as a general cure many would advise adding 1tbls/gallon of salt to the quarantein (sp) tank and boot the heat to 90. make sure the params are the same or the fish may get shocked my the diff.
if you have any more info, or pics to share, it may be more helpful.
hth kimberly :-*