Friends have taken the smaller of our aquariums - I know it's in good hands with a smart young lad. When we were carrying the many parts (and jugs of water) up to the system's new home, a neighbor told the new eight-year-old owner, "I'm going to get you some fish!" To which the boy responded, "Actually, it's best if we wait for five weeks before adding anything else. That way the aquarium can stabilize. Also, it's a small aquarium so it can't support too many more fish."
Which was the perfect answer.