Personally I wouldn't worry about this at all. I am sure you will receive lots of advice from folks that would worry about it but unless you are on a time crunch to get fish in this tank as soon as possible, I would say that in the balance of time everything will be fine. It will still take 1 month to cycle the tank if you leave vs if you stay. You can always put fish in before that but I find that things are easier and better if you just wait the 1 month. Yes you can just throw in something that decays. It takes a few days for fish food to break down so you could just "ghost feed" right when you are leaving, but if you don't want to leave the tank 'dirty' then I wouldn't bother. But I also prefer to take the slow approach to things so /shrug.