Red coloring on tang

[sk8boarder]

I recently put my blue tang into QT after a freshwater bath with formaldihide. I put him into the QT because he had ick. The QT tank also has some copper in it, but very minimal (1 ML in a 10 gal tank). the visible signs of ick are gone but the tang is bleaching and getting a rosy red tint in his lower stomach. Does anyone know why this is and what i can do if it is harmful for the fish?

 

[Percula9]

It could be secondary bacterial infection. Treat with an antibiotic.

 

[sk8boarder]

and he also has not been eating. I have put pieces of seaweed with garlic on it but he has hidden behind one of the PVC pipes and has not come back in a while. any suggestions on how to get him to eat?