Malachite green is not a very effective treatment for C. irritans
but will sometimes get lucky
It could also be the cause of your fish's lack of appetite. Formaldehyde and copper treatments do have the habit of supressing the fish's appetite. In some cases the cure can be worse than the problem being treated. One reason hyposalinity in a seperate quarantine is preferable. It does not have these kinds of negative effects from the treatment itself. Has the treatment been successful and when will you be able to remove the med?
You could try soaking the foods in a drop or two of garlic extract. This will often spark a feeding response in the fish.
, I deleted the duplicate thread... 8)