The fish tank is the most important thing for your fish. Goldfish get their air from the surface, so get a tank that has a lot of surface area. In order to calculate the surface area, multiply the aquarium's length in inches by its depth in inches. For every inch of your fish's length, you must have 30 square inches of surface area. So if your fish is three inches long, you need 90 square inches.

Your goldfish needs to have the water at the right quality to be healthy. Tap water is usually okay to use, but try to let the faucet run for a minute or so before taking any water. Before you use the water, you need to let it sit out overnight. This will get rid of any chlorine in the water.

The water in your tank must be kept clean. You can accomplish this by doing water changes. Don't change all the water at once though. You just do a partial water change. About once a week you should do a 30% water change. If your tank is ten gallons, then change out three gallons of the water. Remember to let the new water sit out overnight before putting it in the tank. Take out the three gallons of old water and slowly add the 3 gallons of fresh water. The best way to remove the water from the aquarium is by using a siphon hose. You can also use this to vacuum the gravel.

Your goldfish will need to be fed every day. There are many commercial goldfish foods that will work fine. Be sure you don't overfeed your fish though. Don't feed more food than they can eat in a couple of minutes. If they don't eat all the food, you should remove it from the tank or it will make the aquarium dirty.

A filter for your tank is highly recommended. This will keep your water clean and remove and impurities in the tank. An external box filter works great because it doesn't take up space in your tank and adds more oxygen for your fish.

There are also a few other things you will need for your tank. A hood should be added to prevent any fish from jumping out or dust falling in. An airstone should also be put in the tank. It puts bubbles into the water which keeps the water oxygenated. At the bottom of your tank, you should put an eighth of an inch of gravel. Your goldfish will really like this.

If you do these things for your fish, they will be very healthy and happy. Try to watch your fish everyday so you will notice if they are acting strangely. If they are acting funny, something in your tank is probably wrong.