Do not overstock

The first basic rule to healthy fish is NOT to overstock. Use at least 10 gallons of water per goldfish, more for commons and comets.

Plan for the Future

He may look like a tiny thing but goldfish live long lives and grow continuously. You need to cover the tank as goldfish may jump.

If you take care of the water, the water will take care of the fish

• Treat your tap water with a high quality tap water conditioner that will neutralize chlorine/chloramines and detoxify heavy metals from your tap water.
• Measure it for ammonia, nitrite, nitrate, pH to make sure the water is stable and non toxic.
• Filter it. The filter on your goldie tank should pass the tank’s entire water volume through the filter at least ten times per hour. Your filter traps trap debris and particles in your tank and also serves as a home for the bacteria that keep the water happy by converting ammonia (toxic) into nitrIte (still toxic) into nitrAte (less toxic). It will take several weeks to establish your biological filter (the good guy bacteria). Read about this process called cycling here.
• Perform partial water changes weekly or biweekly (20-40%) to take care of the waste not dealt with in the biological cycle and to replenish the minerals and other good stuff the goldfish have used up.
• Clean the filter by rinsing filter media (the fuzzy stuff) in some tank water twice a month.
• Clean the gravel. Vacuum parts (but not all of it) every time you do a partial water change. "Nasties" may hide there that will pollute your water. Debris (fish poop, uneaten food, etc) build up and the bacteria that consume debris produce ammonia. If areas build up that don't get good water circulation, it can produce toxic gasses.

Goldfish are living beings and need oxygen

• Provide large surface area. Goldfish fare better in tanks that are long, rather than tall. Longer tanks provide a larger surface area for optimal gas exchange.
• Make sure there is surface movement. If the filter does not provide movement add some airstones.
• Do not overstock. More fish means less oxygen per fish.
• Perform partial water changes and tank cleaning weekly. Your tank maintenance assist oxygen production because as you remove dying plant, debris and uneaten food you reduce the number of oxygen consuming bacteria.
• Watch for gasping. If fish gasp you may have a problem related to oxygen.

Goldfish have preferences

• Keep a stable temperature around 76F
• pH should be over 7 (preferably over 7.4). However if your KH (which measures your alkalinity) is low (under 80 PPM) you may see pH swings and if you experience pH drops between waterchanges you should look into increasing your alkalinity (KH) so your pH stays stable. Crushed coral or crushed oystershell added to a high flow area can also be used to increase KH and keep pH stable.
• Some hardness (GH) makes for happier fish
• Lights. Goldfish need to see to find food and have fun. Unless your room is bright add artificial fluorescent light. But remember that goldfish do like dark periods as well.

Goldfish are creatures of habit. Keep things stable

• Don't tinker too much. Goldfish adapt to a wide range of pH and hardness. What they really need is for you to keep it stable so they do not have to adjust too often.
• Use a heater to keep the temperature stable. Goldfish can adjust to a wide range. But around 76 Fahrenheit is a good temp for most fancy varieties.
• Use a thermometer to measure temperature. And make sure the temperature of the change water is the same as the temperature of the tank water.
• Test your pH every week and check the pH of your tapwater often.

Goldfish tanks should be about goldfish

• Decorations. Keep them to a minimum. Goldfish need room to swim. They can get stuck between or under decorations. Avoid sharp decorations that they could get hurt on.
• Substrate. Gravel can provide a home for the bacteria that convert ammonia to nitrAte, however it also provides a breeding ground for bacteria that eat debris and can cause disease. Gravel can also be a hazard if goldfish swallow it or get it stuck in their throats. Either use a shallow layer of gravel small enough to pass through a goldfish, or use a single layer of larger rocks too large to fit in their mouths. You can also have a bare-bottomed tank.
• Tankmates. It is easier to succeed with a goldfish only tank. Tropicals have different requirements and are often sensitive to goldfish medications (like salt). Common Plecos and apple snails do not make good mates as they may suck on goldfish slimecoat and harm or injure them. Smaller hardy snails like trapdoors or small ramshorns would work fine though.
• Plants. Plants can be used with goldfish but not always with success. Goldfish like to think of plants as their own salad bar and you may have to try a few before having success. Good ones to start with are java fern, anacharis, java moss, sword plants, dwarf anubias and Crypts. For more information, see our article on Goldfish and Plants.

Goldfish are omnivours and need good varied food to be healthy and happy

• Feed goldfish once or twice a day (more often if they are babies and juveniles)
• Feed a varied diet
• Do not overfeed.
• If you feed dry food (pellets or flakes) make sure they are good quality ones and not too old
• Feed a varied diet of shrimp; krill and some live foods such as daphnia and worms. See our Goldfish Diner for more ideas for healthy goldfish foods.
• Omnivours like their vegetables. Feed washed greens, spirula, peas, oranges and more.
• Some goldfish are sensitive to dry food - particularly dry flakes. You may have to presoak your dry food or if see problems (like flipover) eliminate it from the diet
• You can find more information in our goldfish nutrition articles.

Plan for the unexpected

• Goldfish can get sick so keep your medicine cabinet stocked
• Quarantine new fish (three to four weeks) to prevent illness spreading
• Have a Hospital Tank ready (or something that will work as a make-up tank) just in case.

Be the best veterinarian you can

• If fish get sick or out of sort try make a specific diagnosis rather than poison fish with too many medicines.
• Always check your water first
• Isolate sick specimens
• Come describe what's happening in our Sick Fish Forum and we will try and help.

Thus plenty of water, generous space, regular water maintenance and good healthy food and your goldie should enjoy a long happy life with you