When I go on vacation, our UK members would call it holiday, I just let it be an interruption in normal tank maintenance. That means that the regular water changes happen as normal right up to the day that I leave. As far as the fish know, food suddenly stops arriving and they must deal with old water for an extra week or two. The end result is simple to state. My fish do just fine with an absence of one or two weeks but the fry seem to disappear after an absence of 3 or more weeks.