Is a 2 gallon bowl too small or too large for a goldfish?

It is much too SMALL. 1 goldfish needs a minimum of 10 gallons of water. It must also have a permanently running 'cycled' filter and it must also have at least 50% of its water replaced every week. It is preferable to keep the goldfish in a larger tank so that two or more can be kept, as goldfish are social fish.

A two gallon bowl would be suitable for a single male betta IF and ONLY IF a suitable small filter can be found that does not disturb the surface of the water too much, and a heater can be found that does not present an electrical hazard in such a small tank - 25 watts or less. If no heater is available, you could keep a single paradise fish provided the tank has a filter. I strongly recommend that you don't attempt to keep any fish in a tank smaller than 5 gallons, especially if you are a beginner, because it is so much more difficult to keep the water quality good in such a small volume of water.