I do work with risk assessors and have pondered this. Here are my overall thoughts not necessarily to due with infants:
My biggest fear would be electrical honestly both electrocution and fire. So making sure your cabinet and other electrical is secure. Same goes with the tank and other open water (I think about this with my foster kittens).
Then there are chemicals we keep because of our tanks. I would have all the chemicals we put in our tanks secure. Most aren't that bad but everything is poisonous in big enough amounts.
Next biggest threat IMO is infection which is more a risk to us who reach into our dirty tanks full of bacteria and sharp organisms. Obviously we should all be washing hands after touching our tanks especially if you have cuts on your hands.
Finally there are the fish and inverts. I know you don't keep anything stupid but here are some common things:
- Palythoa and zoa as you mentioned.
- Fish spine venoms are rarely deadly but very painful.
- Puffers are deadly if eaten but only if eaten.
- Some blennies have a venomous bite with a very strange but not very dangerous venom.
- There is a slight risk of cone snail hitchhikers and I think everyone should know what they look like because they are potentially very dangerous.
Overall it isn't the stuff in our tanks that are dangerous really. Its the things surrounding.