I have a 13 year old son.
He lets me do all the fishy chores, because quite frankly it doesn't appeal to him at all.
We were in WalMart one day right before his birthday and there was an appeal made by me to one of the employees there to tend to a betta that was covered in fungus, shredded fins, etc. - the employee told me they don't treat sick fish, yadda yadda - I stomped over to put the fish back on the shelf and my son said "Mom, I know what I want for my birthday - I want to save that fish. Please?"
So we ended up with what turned out to be a wonderful fish, Jack.
Turns out that a few months later, I thought getting a PUR water filter would be a good idea for my fish tank changes. Well, I ended up killing little Jack with the major PH swing the filter created in the water.
My son was right there in his room with me when I put Jack into the tank - he saw him flip over upside down, and we both watched him die.
It was a great life lesson learned by him - that animals that we have for pets WILL eventually die. It was a horrible thing for me because I had to see this beautiful fish die from my mistake. BUT... I think him watching me do something a bit differently with my fish than I normally do made him realize just how fragile they really are. He's obviously old enough to know better about the whole situation, and I highly doubt he would ever try to do anything with these fish, but this incident sort of cemented the whole idea of him ever making an attempt to do anything with the fish.
What a HORRIBLE scene it must have been at that man's house. How heartbreaking for everyone.