that's the problem with sensitive angels like golden, colini, venustus, multibar, rock beauty and bandit.
they respond very poorly to treatment and will go on a feeding strike during this period. The bad news is, you will need to re-train it to feed all over again even after removing them from the medication. these are very delicate fishes and you cannot stress them too long by treating them.
these fish are usually not given QT treatment because they cannot stand being in bare tanks with medication.
the best form of treatment for these fishes are hyposalinity. it's the least stressful for them and they will still continue feeding. but hyposalinity is not a good treatment method for non-feeding classes of sensitive angels. liverock and macroalgae cannot be offered during hypo and being in a bare tank, they will slowly starve.
that's why these fishes are so tricky. i wish you all the best!