One fish down, one more affected, please help

Two days ago, my yellow-eyed tang presented with what looked like a nasty case of ich. Seemed fine on Sunday, Monday night was covered in white spots. QT is  having issues (wonderful timing) and wasn't exactly how to treat (because of corals) so did a fresh water dip last night. Upon closer examination, you could see several patches where there were no scales. He was on the bottom of the tank the morning and I put him down. Tonight, my yellow damsel is rubbing up on stuff and you can see several patches of scales missing. No ich. I don't know what to freaking do or what in the heck I'm dealing with. THoughts?

 

upon closer examination of the damsel, the scales look like are losing a little bit of closer, almost dirty in appearance. A little bit raw. Fiance thinks he can see little black dots on it.