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How to Make a Goldfish Live for Decades

Believe it or not, a goldfish could live for 10-25 years or longer if it's given proper care. However, with normal care it usually lives for about 6 years. The Guinness Book of World Records cites a goldfish named Tish that lived 43 years after being won at a fair in England in 1956![1] Now you can help your scaly companion survive into the "golden years." It can be easy to forget that stress and hygiene can affect your tiny little fish enormously, but controlling those factors can have an enormous impact on your fish's lifespan. Little changes such as frequent water changes can help your fish live long past its expiration date.


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    Get the largest possible tank. Do not use a fish bowl; At least 75 liters (20 gallons) is necessary to make quality life for a single fish. Choose a tank with large surface area to increase the amount of oxygen in contact with the surface of the water (wider is better than taller).
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    Set up the tank prior to the purchase of a goldfish.
    • Getting it ready may take two or more weeks. It is necessary to build up enough good bacteria to break down the fish' wastes. To do this, do a "fish-less cycle". Once completed, your goldfish aquarium will have more than enough bacteria to break down fish waste. Failure to cycle a tank will result in ammonia poisoning and death.
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    Provide mental and physical stimulation for the fish. Decorate tank with gravel, driftwood, hardy live plants, etc. Be sure that any decorations you choose aren't hollow (harmful bacteria can grow inside) and that they don't have sharp edges (your fish might tear its fins). Provide your fish with different areas in the tank, such as an open area ideal for swimming and a hiding area.
    • You can also train your fish various ways. If you feed them at the same time every day, they will soon be waiting for you at that time and grow used to your presence. Soon, you can teach them to eat from your hand. You can also use a fishnet with the netting taken out as a 'hoop' and train your fish to swim through it.
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    Add some equipment to increase oxygen diffusion into the water. A small air pump and air stone can be sufficient. You can also have the current from a 'waterfall' type filter help agitate the water's surface.
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    Clean the tank at least once every two weeks, but more frequently is preferable due to the large amount of waste goldfish produce. Consider buying a filter, because goldfish produce a lot of feces, which can lead to a buildup of ammonia and nitrites, which are potentially harmful to your fish. If you don't have a filter, clean the tank twice a week. This is essential. How often you do this will depend on the size of your tank, the number of fish, and the effectiveness of the filter. Real plants are great as they will help absorb some of the ammonia, nitrites and nitrates.
    • Frequently test for ammonia and nitrite (you want both to measure zero). A pH test is also handy to ensure your goldfish's water is not too alkaline or acidic. This can be purchased at any pet store. Do not modify the fish's water, however, unless it is significantly different from neutral. Goldfish can tolerate a wide pH range, and pH modifying chemicals are not a lasting solution without more consistent monitoring than most people will do. A range of pH 6.5-8.25 is fine. Many municipal water supplies buffer their water up to around 7.5, and goldfish will live very happily in this range.
    • Do not remove the goldfish during a water change. Using a gravel vacuum to suck debris out of the gravel can be done with the fish in the tank. Frequent partial water changes are much better than full (and stressful) water changes.
    • If you do need to catch your fish, consider using a plastic container rather than a net, as the fish can injure its fins and scales while thrashing around. This also increases stress! If a net is the only option, soak it prior to use. Dry nets are much more likely to cause injury than wet ones. When using a plastic container, be careful and let the goldfish go in by itself, or it could be hurt.
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    Allow the water temperature to change as the seasons change. While goldfish don't like temperatures over 75°F (24°C), they do seem to like seasonal variations where the temperature falls to the high 50s or 60s (15-20°c) in the winter. Fancier goldfish are an exception and cannot easily tolerate temperatures below about 60°F (16°c). Be aware that goldfish will not eat below 50-55°F (10-14°c).
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    Feed the goldfish one to two times daily with food specifically designed for goldfish. If you choose to feed them more often, then reduce the size of the meals so you don't overfeed. Give them only as much as they can eat in a few minutes, and clean any leftovers immediately. If a floating food is used, soak it in water for a few seconds before feeding so that it will sink. This reduces the amount of air the fish swallows while eating, which in turn reduces the risk of buoyancy problems.


  • Be sure to regularly clean leftover food and waste from the gravel. You can do this by using a gravel vacuum.
  • Be careful where you place your tank. Don’t place it near a heater, or AC. Don’t place it near a window or door. Doing so can cause your tank to change temperatures rapidly or in the case of a door cause it to get broken when the door opens. Don’t place it somewhere where the sun shines on it throughout the day. Doing so can cause the tank to overheat and also causes algae to grow.
  • Make sure not to have sharp ornaments. If you do, it may rip the fins off your goldfish and take off some of the scales on your fish.
  • Be careful when transporting your goldfish. Stress can reduce their lifespan.
  • Make sure the fish looks healthy when you buy it, and if any of the fish in the tank seem sick (white spots, red spots/velvet, of pine-coning scales/dropsy) then do not buy from that tank. It is better to come back to the store in a week and buy a healthy fish than to bring home a fish that will need special treatment or even die in your care. New fish should be quarantined away from the other fish to reduce the spreading of parasites, bacteria, and fungus.
  • Do not leave the tanks light on for more than a few hours at a time. This can lead to the water over heating and also causes algae growth. Even if you have real plants, 8 hours/day is enough time for lights. You may want to set your lights to a timer so they turn on/off automatically and help your fish maintain a natural rhythm. Also, when turning the lights on and off try to always turn on the room lights first so it isn't a sudden shock for them. They don't have eyelids, and sudden changes in light can scare them.
  • If you have a cat make sure the tank is not open top.
  • Common, comet, shunbunkin, and some fancy goldfish can grow to be over 12 inches (30.5 cm) long if put in tanks or ponds that are large enough! However, contrary to popular belief, fish do not stay the size of their tank. Do not purchase a too small tank and expect the fish to stay that size, as this may reduce life expectancy and may cause stress.
  • Monitor your water conditions regularly. Take care of the water temperature. Test for nitrate, nitrite, and Ammonia. Test your water for pH, hardness, and alkalinity initially. Do some more research on that topic.
  • It is unhealthy to overfeed your fish. Only feed your fish as much as they can eat in 2 minutes. Also, do not add the food all at once, but rather add one pellet or flake at a time and give your fish time to eat. You do not want any food to fall onto the gravel while you are feeding.
  • If the air pump is too strong for the size of the tank, you may place a clip or commercially available valve on the tubing and reduce the amount of bubbles.
  • When using weeds from nearby ponds to give your fish a natural habitat, it is important to rinse it first so that you do not spread parasites to your goldfish.
  • Never use a tank under 50 liters unless it is temporary (i.e. less than a week). Anything smaller will stunt the fish leading to many health problems, and is cruel.
  • When treating a sick fish you don't always have to move them to a separate tank.
  • If you are worried about the quality of the tap water in your area, call your local pet store and ask if the water is usable for fish. Your local government should be able to give you a water quality report if you have city water. This report will give you an idea of the local water chemistry. Also, there are many brands of dechlorinators, and other types of liquids that can help maintain a healthy environment for you new "golden friend."
  • Take care if your fish properly.
  • Always use a filter that will cycle ten times the amount of water in the tank I. E if you have a 20 gallon tank, you will need a filter that cycles 200 gallons per hour.
  • Don`t buy any fish with small tears in any of its fins. It could be the start of a horrible disease called fin rot. Be sure to check that your fish looks healthy before you buy it!
  • Do not use soaps, bleach, or any other cleaner to clean in the bowl other than what is suggested by your vet, as you could kill them.
  • Do not poke or prod your fish if it seems dead, unless it is belly up or pale and rotting. One way to tell if your fish is dead is if it is very stiff, another, if it's gills are not moving at all. If your fish dies randomly, think back to what you may of done that caused your fish to die. Over feeding and poisonous food is a big problem with most deaths. So if you have a goldfish, don't over feed it!
  • If you have fuzzy looking growing at the bottom of the tank, in the gravel, it's algae. You should get a snail or a plecostomus. The only problem with snails is that they can lay parasites on the fish that can make them itchy.


  • Be sure there is no soap or detergent residue in the container used for water changes. This is poisonous to fish.
  • Do not use any type of cleaners or acids to clean the tank, it will harm and causes stress for the fish
  • Many cities put chloramine in water rather than chlorine. Chloramine does not evaporate and must be removed by adding an additional chemical. Check the label of your dechlorinator to ensure that it also removes chloramine.
  • Use caution when mixing fish! Goldfish should usually be kept only with other goldfish and some breeds of goldfish should not be mixed. Your fish should all be of about the same size, and be able to swim at the same speed, i.e. do not mix comets with fancy-finned goldfish because the comets will eat the food before the fancy goldfish can get there.
  • Make sure to put a check valve in the air line when using an aerator. Not using one can allow water to siphon back down the air line into air pump causing damage to the pump. It may also cause a fire if the water reaches the electrical wiring in the pump. Also make sure the check valve is installed correctly.
  • Although a water heater is not necessary in a goldfish tank, if you do use one use it with caution! Water heaters, especially ones of cheap quality, are prone to malfunctioning and can stay on even after they are set to turn off, so monitor them with a thermometer. It is general practice to replace your heater every two years, and only buy from well-known brands that have warranties.
  • Comets, common, and shunbunkin goldfish grow up to 1- 1 and a half feet long, so be prepared for your little friend you won from a carnival game to grow to a vast, orange, behemoth.
  • Fish cannot filter feed, so don't expect the fish to live long periods of time without fish food.
  • Never place a tank on a weak or unstable surface. Without a stable stand under it, the tank can crack and leak. If the table collapses it will cause the tank to fall and break, and your fish may suffocate.
  • If you use aquarium salt in your tank, use it with caution. Salt does not evaporate and is only removed whenever you remove water from the tank. Only use when treating injured/sick fish.

Things You'll Need

  • Aquarium
  • Fish
  • Gravel
  • Decorative objects
  • Complete Water Test Kit (Ammonia and Nitrate essential)
  • Filter
  • Air Pump
  • Plants
  • Thermometer

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