I agree 100% about not feeding your fish while the pp is still in there. Personally, if I ever have to medicate my pond, or treat a fish in isolation, the number one rule is not to feed for a few days after the treatment as well. Not had any problems.
Incidently, here in the UK it is not uncommon to not feed the fish for four or five months over the winter period. Again , no problems, for me anyway.
Been at it for 20 odd years so I must be doing something right.
Chris