It seems there are several issues to be concerned with.
The host has a responsibility to protect the lives of the fish and the child. He also must try to be gracious while being a responsible community member--It takes a village to raise a child.
The guest, if reared well, will take responsibility for her and her child's behavior, regardless of the host's grasciousness. She will find a way to teach her child his responsibility for the consequences of misbehaving. It's called teaching with logical consequences where I work.
I believe children can be taught to be respectful of other's property and should be taught so early. It doesn't take a tissy fit to train a child. Respectful and responsible training will do it. Children must learn respect and be expected to behave so.
I am a little horrified at young men and women treating others' property without respect. It is mostly poor upbringing.
My companion dog, Whiskers, doesn't like children. They have thrown stones larger than him at him over the fence. When I tried to socialize him with the girls next door, they screamed and ran and acted in a way that confused him. He thought children were rabbits to be chased.
He is mature now and for the most part leaves them alone if they respect his space. I can tell a responsible Mum in public: She always approaches me with her child's hand in hers and asks "May my child pet your dog? He is so cute." There are even very young children that always ask first. It warms my heart, and I always complement them on their behavior.
Some children I have to watch because even though I have warned and told them "no" when I saw them approaching without supervision, they continue to sneak around me trying to sneak up on Whiskers. I can only assume that they don't trust or respect adults. These are the same type of children that would throw stones when I and their parents told them no.
Forgive me for my hijack, just thought there was a perspective not quite addressed.
I'm so sorry about dumbass, jaimoe, and happy for your gourami.
. I honestly doubt I'll ever want them. I never have wanted a baby, even as a kid when every little girl wants a baby doll to take care of. 
)
Should it ever happen again though that sounds like a good idea! Oh and thank you everybody for your condolences! The good news so far is that the second gourami that I thought would die seems to be doing OK for now.
