big white patch on Royal Dottyback

[i love fish]

I purchased a Royal Dottyback 5 weeks ago which had a huge white patch on its side right after its pectoral fin. It didn't look serious so I thought I'd be able 2 treat it.
Up until now the patch is still there, no better, no worse, she's still eating and acting normal, no other signs of problems or disease.
The meds I tried where: pimafix, melafix, and copper. No change in conditon at all.
Any idea what this patch is and how 2 treat it? Sorry I can't provide pictures, but is appears that the patch is like a pale area underneath the scales, not a thickening of the mucus layer or anything like that.
thank you

 

[mboswell1982]

hey fish, sorry to hear about your dottyback. now, the things we are going to need from you are pictures of the affected fish, and as good a pic as you can take of the infected area. also, we're going to need to know what your water parameters are, any tankmates of the fish, and the size of your tank. also, do you have a quarantine tank set up?
..............sorry for the punctuation, its not my strong suit