Thank you all for taking the time to read and reply to my post
I think since the kole is eating and behaving normally I will leave him in the DT for now and continue feeding with garlic. If he gets worse however I will move him to a QT and if I see it drastically spreading to my other fish then I will consider moving all the fish to QT's for treatment and leave my DT fallow for 12 weeks. I really hope the latter won't be necessary...
Mark and
halwake, you both said you had ich in your tanks before but it eventually subsided on its own. Does that mean it died off completely? Or the fish are just co-existing with it? I think I'm going to pick up a couple of cleaner shrimp this week and then I will not be adding any more livestock to the DT for a good 2-3 months after the last white dot is gone.