I have a child that is 2. Loves and respects the tank and creatures. When she wants to look and explore the specimens, we put a thin pair of cloth winter gloves on. No finger or handprints on the glass. I'd be more afraid of 4 to 6 age range. Lots of stories of flying toys, coins/toys/candy dropped in, juice/soda poured in, a packet of pellet food dumped in. A thread on this site from many years ago a girl caught her nephew taking a pee into the sump. Keeping the cabinet locked, no chairs to push over to it and climb up. Lots of barricades available that can be easily be folded up and stored away while the child is not over for a visit. I see this post is a month old, hope everything has gone well and the child has shown positive interest in the animals inside.