It's not recommended to put goldfish in a fish bowl because of the lack of space and fresh oxygen.

Remember, goldfish won't stop eating and growing, they'll fill the bowl with waste and carbon dioxide very quickly without any kind of filter.

If you'd like an aquarium, start out with nothing less then 10 gallons (desktop aquariums), 20 gallons or more you'll need a stand.

Think about how big the fish will grow to be, and about the posibility of live plants, they'll need a taller tank to properly grow.

You'll need a filter and a heater properly sized for your tank, if you're not sure what to get, bigger is better.

Before you add any fish, it's wise to cycle your tank to make sure the water is clean and ready for your fish. This can take 2 weeks to a month and a half.

When goldfish were first domesticated they were kept in big garden ponds.

Most of the oxygen is absorbed from the atmosphere at the surface of the water. So the greater the water surface, the greater the amount of oxygen that will be available to them.

To ensure your pond wont freeze, keep it about 3-4 feet deep in the center or at the edge, your pond's drain should be located at the deepest spot.

It would also be a good idea to have plenty of water plants to provide our fish with oxygen, shade and shelter.

For your aquarium, the most common and easiest filteration systems are either undergravel or power (pictured), that hang on the back of the tank.

If you choose undegravel filter, make sure the air pump or powerhead has enough power for the tank size. You can't use this type of filter with sand or other fine fillers.

If you choose power filter, be sure to get one that will circulate enough water for the tank size. Ideally 5 gallons per hour (gph), per gallon. Example, a 10-gal tank needs 50gph.

If your tank doesn't come with a heater, a fully-submersible one is the easiest.

Look for one with an adjustable thermostat, since different fish prefer different settings. Most will prefer 70°-80°