Heres what I do..Ill include an example:
''Mommy can I have a fishie?''
''I guess so''
*they pick up the fish and go to the bowls and pick one up*
Me: Excuse me but those bowls arent really good for the fish.
Them: But they say for bettas on them.
Me: True but theyre not good homes. They need a complete cleaning several times a week and you can put a heater in there and the betta will jump out.
Me: Ya they need heating and definately a cover.
*I reccomend tanks, heaters, filters, food, and give them my website and this sites adress*
99% of the time they listen...the rest they just put the fish down...