I bury all my departed fish in my houseplants. Good fertilizer! - I usually recant something about ashes to ashes, dust to dust.... The sound of the flushing toilet would probably get in the way of the verse.
Fortunately, the boys never really got too attached to them. They lived in the window sill of the kitchen and I took care of them, thinking they were a little delicate for the boys just yet. We've had them for forever and they never turned into frogs! I tried to follow the directions that came with them and as far as I know I did everything right...I don't know what happened. I feel a little bad about it.
I hate for anything to suffer and I hope I didn't cause these creatures to. Once, I captured a huge black widow out in the yard with the intent of preserving it as a specimen for the boys. Pouring alcohol on it was supposed to kill it immediately, according to my entomologist friend. Well, I poured the alcohol on it and it swam around frantically for what seemed like forever. Probably just a minute or two at the most. I was mortified. Then I found out my alcohol wasn't 70% like normal, but cheap 50% and that's probably why it didn't kill it right away. I felt really bad about that.