see a smart idea for liek a "vacation food" would be like a slow disolving tablet that had no ill effects, but after say a period of time, 3,7,10 days it erodes to the point where real food can come out, pellets, brine shrimp, bloodworms, whatever. That be interesting.
But yeh a week to 2 weeks is usually good unless u got some rare or higher difficulty fish. Also on that starving for a 1 day benifit thing, ive also heard that. Its both "supposed" help the fish's digestive system clear out so he doesnt get clogged or what not, and both give a 1 window for bacteria to maintain higher quality water. I sorta like but question that theory, yeht he fish part kinda makes sense, but 1 day without food, bacteria could die off.... i dunno HTH