I killed Nemo!!!!

We have had a Beta fish for over two years. He has lived through non-frequent water changes, over feeding, forgetting to feed...he was a hearty fish...well, so I thought.
Today, I was cleaning the bathroom where he LIVED and I was using a lot of chemicals, so I thought that it would be nice for me to move him out of the fumy(is that a word?) room. So, I put him outside to enjoy some fresh air....fresh COLD air...he seemed to like being outside as he briskly swam around in his bowl. I went back to clean the bathroom, and then on to pick-up Blayne at pre-school...when I returned and went to get Nemo and bring him back in the house, I found him stiffly laying at the bottom of the bowl! I froze NEMO!!!! Oh no! I dipped him out into a smaller container, because I knew that my kids would want to see the dead fish. I told the kids on the way to piano lessons that I had accidentally KILLED their fish....they sat silently and then replied, "mom, can we have a hamster now?"....WHAT???????