Hi..here's a physicians input. I can't think of any risk to the baby from a microbial or fungal point of view by having an aquarium in the house. However, you still need to take the same precautions about baby proofing once the baby turns into a mobile toddler, ie, hanging electrical cords, pulling or knocking a small tank over, keeping fish medications out of reach or choking on small pieces of gravel/rocks etc. Most infections occur in marine situations (vibrio eg), however, it's not inconceivable that anyone handling a dirty filter media with an open cut on their handcould (but probabably unlikely) get a local infection. I hope this helps. SH