Sick fish... maybe

[revnull]

When I bought this Copperbanded Butterfly fish it had a few black clumps on the fin. I thought this might have just been a wound from a bullying tang that was in the same tank at the LFS. In any case, it seems to be spreading. Can someone ID this stuff and maybe recommend corrective action?

Thanks in advance!

http://www.revnull.com/reef/PICT1013_Medium.JPG

http://www.revnull.com/reef/PICT1028_Medium.JPG

http://www.revnull.com/reef/PICT1030_Medium.JPG

[Hunter21]

kinda looks like fin rot....but I'm not totally sure! someone with more experience will chime in soon! :D Erin