I know this is an old thread, but I have a tang with black ich as well...It is my OWN fault for trusting the LFS...I did NOT QT it...'sunshine' is now in my 72gl display, and I can't catch him..nor do I want to attempt to catch him again. I have softies and various shrimp, including a fire shrimp who shows no interest in 'cleaning' the tang.
The tang was added Saturday, and it's now Tuesday evening.
I discovered the black dots Sunday night.
I have been adding garlic to his food..can't do a formalyn or fw dip because I can't catch him...I am afraid if I take apart the tank, it will cause stress to all the other critters...as I JUST did this a few weeks ago trying to catch a mantis who has been in there for a couple years. that's a whole 'nuther post, but the mantis is in the qt tank at the moment.
Anyway..all suggestions appreciated..I sooo hope the black ich goes away once the tang has enough garlic.
Also afraid to raise temp and do hypo because of other tankmates etc.