this is a very specific time we'd want to reduce lighting intensity to avoid bleaching and stressing the nem in the low nitrogen condition. we have a specific thread collecting times we need to stay away from full intensity lighting, I never thought about fallow, its directly indicated on many levels for fallowing tanks *if* the feed is restricted.
if the feed isn't restricted, then no need to lower lighting the fish being in or out wont make a difference.
I guess the only feed I'd withhold would be minnows frozen or thawed etc, but no reason to withhold things like rod's feed or pellets or reef energy etc, just not fish.
*frozen fish might still be ok am not sure, but there's no need to restrict feed in general during fallow.