Hi
i thought i would lay down the basics for newbies

Goldfish should never ever be kept in bowls, The minimum tank size for one goldfish(if you plan to keep one in a tank)is 20 gallons. then for each goldfish added there should be 10 gallons, so if you want to keep 3 goldfish the minimum tank size in 40 gallons.
The reason this rule applys is because Goldfish can live for 20+ years and reach sizes up to 16 inches. Many people think the goldfish can grow to the size of its bowl,well it cant and wont,its internal organs will grow but its skin will stop therefore resulting in death. Theyare probably the messiest non cichlid fish out there to date.They poop alot and if they are in small bowls the ammonia (deadly toxin) builds up and kills the fish
HTH
DD