Goldfish are the classic first fish for the budding fish enthusiast. Goldfish care is relatively easy, as goldfish are hearty, long-lived and visually pleasing. But just because a goldfish can survive in a tiny, unfurnished bowl does not mean that a goldfish can live comfortably or in good health this way.

Proper goldfish care is a balance of careful preparation and routine upkeep that can guarantee that your goldfish has a long, healthy, happy life.

Supplies You'll Need:

Setups may vary, but generally you'll want to pick up the following from the store well in advance before buying your goldfish:

Tank
Hood w/ fluorescent light
Power strip
Tank stand
Goldfish food and care products
Aquarium filter
Gravel siphon
Thermometer
Cork board
Air stone
Airline tubing
Buckets (for water changes, etc)
Aquarium gravel
Ornaments and plants for hiding places
Freshwater test kits

Setting Up the Tank

Goldfish are not quite as temperamental or delicate as tropical fish, but there are a few things to consider to keep your goldfish comfortable.

Choosing a tank size

Goldfish need plenty of room to swim, and the more or bigger goldfish you have, the bigger the tank you will need. To figure out how many goldfish a fish tank can accommodate properly, find the surface area of the tank (length x depth) and divide it by 30. This number is the amount of inches of goldfish that can live in the tank.

For example: If a tank is 18 inches long x 12 inches deep, the surface area is 216 inches. Divided by thirty, it is about 7 inches, meaning you could keep about 7 one inch goldfish or three goldfish just over two inches long.

Tips for goldfish tank placement

Keep your goldfish tank out of direct sunlight. Sunlight promotes the growth of algae and overheats your water - goldfish are cold water fish.
Make sure the tank is within range of all the proper appliances like the sink for water changes and a power outlet for lights, and filters.
Tanks can be very heavy when filled with water. Make sure you place yours on a special stand or a very sturdy piece of furniture.
Place a sheet of corkboard underneath the tank to keep it even and stable.
Keep the goldfish tank away from high traffic areas or very noisy areas.
Drafts cause harmful fluctuations in temperature so keep the tank away from doors, windows and vents.

Washing the tank

Rinse out the tank with plenty of water, use a hose or your kitchen sink's sprayer attachment. Make sure to remove any soap residue. Dry it thoroughly with paper towels.

You will also need to wash the gravel thoroughly. Place some gravel into a bucket of water and stir vigorously. The water will become cloudy with debris. Pour the water out, rinse and repeat this process until the water remains clear after stirring.

You should rinse any equipment or decorations that will be submerged in the aquarium, even if it is brand new.

Adding gravel

If using an under-gravel filter, install it before adding the gravel. (More on filter choice later.) Place a couple of handfuls of gravel on top of the filter first to stabilize it and then fill the bottom of the tank with as much gravel as you'd like. About three or four inches is ideal for securing plants, tubes and air stones.

Filling the tank

Place any decorative rocks or ornaments before filling - you want to provide your goldfish with hiding spots to reduce their stress. Avoid rocks from your yard or anything not meant for aquarium use, they could transfer harmful microbes into your tank or affect water conditions. Make sure they are sufficiently buried in the gravel and secure.

Goldfish are hardy and can often survive in tap water, but if you want to be on the safe side use a tap water conditioner to reduce contaminants. Run the faucet for about thirty seconds to reduce the amount of heavy metals in the water. Now, fill up the aquarium about half way. Make sure the water is not flowing vigorously or it may disrupt the gravel.

Readjust the gravel if necessary and add any plastic plants, tubes or air stones at this time.

Live plants aren't a good idea for goldfish tanks as goldfish like to dig and will dig them up.

Once everything is setup inside the tank, fill it to about one inch from the top.

Setting up electrical equipment

Obviously, electrical components in a water environment can be hazardous. Before plugging in the equipment, make sure all of the cords are dry and are not frayed. Make a "drip loop" in the cord - situate the tank so the cord is loose enough to bow downwards in a U-shape before reaching the outlet, or attach a small weight to the middle of the cord. This will prevent water from traveling down the cord and into the outlet.

It is a good idea to let your aquarium run for about two weeks before adding your goldfish to let it cycle. You can use cycle aids to speed up this process.

Acclimating your Goldfish

Traveling from the pet store to your home and then into a new tank can be stressful, even traumatic for a goldfish. Follow these steps while acclimating your goldfish to make this transition as gentle as possible.

Bring a paper bag with you to the pet store. Goldfish are sensitive to light and moving from indoors to outdoors can be shocking, so place the clear plastic bag they are in into a paper bag before traveling.
Keep the trip short and smooth. Car rides will jostle goldfish and temperatures can fluctuate faster than they prefer. Insulate your bag and keep your goldfish away from direct sunlight or heating vents.
Dim the lights in your home before bringing them out of the bag.
Float the bag in the aquarium. Do not open it yet, wait for the temperature of the water in the bag to adjust. This takes about fifteen minutes.
Add a little bit of water from the aquarium into the bag. Repeat this step until the bag is mostly aquarium water.
Let your goldfish swim free! Open the bag and let it swim out on its own.

WARNING: If you are adding a fish to a tank with other fish in it, keep it in a separate quarantine tank for a couple of weeks to make sure it is healthy before introducing it to the community.

Caring for your Goldfish

Water

Goldfish, unlike most other fish, can easily survive in normal tap water. But make sure you change 25% of the water out on a weekly basis. Before adding water to a tank, let it sit out in a container for about 24 hours to let chlorine evaporate and the water to reach room temperature.

Feeding

Goldfish will eat almost anything. They are known to eat flake food, cooked peas, and even larvae. Ensure a balanced diet in your Goldfish and buy specially formulated goldfish food.

Flake food is preferable to pellet food or other types of sinking food. Food that floats on the top of the water is easier to clean up and easier for the goldfish to find.

Learning how much to feed your goldfish takes a bit of observation. It is important not to overfeed your goldfish, as uneaten food will pollute the tank. Feed them only as much as they will eat in a few minutes and promptly remove any leftover food or debris with a net or siphon.

Feed your goldfish only once a day. Don't overfeed them. You can use an automatic feeder if you have trouble keeping track! Or if you're going out of town for a few days, try a goldfish food time release block.

A properly fed goldfish is livelier, more brilliantly colored, lives longer and is hardier against disease.

General Goldfish Tips

Because goldfish are cold water fish, and most aquarium fishes are tropical, it is easiest to raise goldfish in a community of other goldfish (or in a pond with koi). Luckily, there are many different varieties of goldfish, including "fancy" goldfish, all with the same basic care requirements.
Goldfish water should never rise above 73 degrees Fahrenheit and ideally should be between 65 and 68 degrees. Keep a thermometer to make sure you don't have dangerous temperature fluctuations.
Water should not be changed all at once, a weekly change of 10 to 15% of the water is sufficient for tanks 10 gallons or more, or in a smaller tank, 25% weekly.
Filters keep the water clean on a 24-hour basis. An external power filter will not take up any space within the aquarium, or you can use an internal filter. It's good practice to combine with either an undergravel filter or sponge filter for adequate biological filtration, as other filters won't usually have enough surface area for this crucial process.
An air stone or bubbler agitates the surface of the water, releasing harmful chemicals and oxygenating the water. If your tank is larger than 10 gallons you may also need an air pump for proper aeration.
A hood or canopy keeps foreign matter from falling into the tank as well as the goldfish inside the tank.
When choosing gravel, choose rocks large enough that the goldfish will not swallow them.
While a goldfish bowl may be an attractive classic, they do not offer as much room or surface area as a goldfish is usually accustomed to.
Keep your goldfish stress-free and comfortable to reduce the chances of disease. Decorations and hiding places are good for a goldfish's mood. Stress relief products or vitamin supplements can also help if your goldfish seems stressed.
Don't forget to clean your filters and cartridges from time to time to keep them running efficiently.
Enjoy your goldfish! They are happy, hardy fishes that with proper care can live up to 15 years.