I don't think it will be a huge issue as long as a water change is performed before leaving and they aren't overfed. Healthy fish can go a long time without eating... I have a fish that spent over two weeks with babies in his moth, then proceeded to breed again a day after having a small meal (and he's still healthy). Sick fish have been known to go for well over a month or more without eating.
My bigger concern is with the water... How big are the tanks? What are in them?
My bigger concern is with the water... How big are the tanks? What are in them?