What is necessary for a goldfish to live in its bowl?

It is NOT very right to keep a goldfish in a bowl. Not only do they become bored and unhappy, but it can cause health problems and stunt the fish's growth. However, the VERY least you can do for a fish in a bowl is the biggest bowl you can find. Also, goldfish NEED some sort of filter to live a reasonable amount of years, and filters cannot be put in bowls. I recommend at least a 5 gallon tank for your fish. Really though, there is nothing special you can do for a fish in a bowl.