To clean the goldfish you put washing up liquid into its bowl.
A childhood belief about general

others believed things like this
- Up until the age of nine, I used to think that Marmalade was made out of goldfish.— Sadie
- I used to believe that the reflection at the bottom of cup of liquid was a crocodile waiting to gobble me up.— Aaron
- I used to believe that arson was a flammable liquid, not the act of deliberately setting fires.— Joey Schwartzman
- I used to believe the Golden Calf produced liquid gold instead of milk.— Trisha
- I used to believe that if I put my arm in the washing machine while it was going that it would rip off.— Hannah
- I used to think that bidets were for washing babies!— Helen