How to Set up a Healthy Goldfish Aquarium

Goldfish are easy to take care of, so long as you have a good environment for them to live in. Here is how to create and sustain a healthy goldfish aquarium.


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    Select your tank. Many people choose to put their fish in bowls, but these simply don't have the capacity to let a goldfish thrive. If you can afford it, try to get at least a 20 gallon (75.7 L) tank for your first goldfish, plus another 10 gallons (37.9 L) for every new fish. The more space your fish have, the healthier they will be.
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    Install a filtration system. Goldfish produce a lot of waste, so a good filter is necessary to keep them healthy. There are many types of filtration, but the most effective one is the bio-wheel filter that hangs on the side of the tank. Undergravel filters are only recommended if you're on a budget or if you're keeping sharpness-sensitive goldfish (such as the Bubble Eye). Canister filters are best for large tanks, as they are a more powerful version of the bio-wheel filters.
    • You want to provide double filtration for the tank in order to keep it as clean as possible. For example, if you have a 20 gallon (75.7 L) tank, get a filter rated for 40 gallons (151.4 L) or two filters rated for 20 gallons (75.7 L).
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    Decide on a heating system if necessary. Most goldfish can function perfectly well in unheated water, but tropical fish may need it a little warmer. For all non-exotic goldfish, the tank temperature should be between 60 °F (16 °C) and 72 °F (22 °C).
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    Put in your gravel and decorations. Since goldfish are scavengers, they tend to put gravel in their mouth, so you don't want them to choke. Make sure the gravel is big enough so they won't choke or put it in their mouth. These are somewhat superficial additions compared to the filtration and heating system, but even the smallest piece of scenery can brighten up the whole tank.
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    Now fill your tank with water treated with water conditioner. Start up the filter and heater according to their directions. At this stage you can also add any live plants you have, but do NOT add your fish before running the system for a few days to make sure it works.
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    Cycle your tank. This step is crucial to the health of your fish. If you want to be really thorough, you can add fish food and let it decompose in your aquarium, which will bring ammonia into the water and cause beneficial bacteria to grow.
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    Test the water. Once your water tests 0 for ammonia and nitrite, but still has some amount of nitrate, you can add your goldfish.
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    Add your fish to the tank slowly. Don't dump a bunch of goldfish into your tank all at once, as this might cause stress to the biological system of the tank. Only add one or two fish at a time, preferably with several weeks between each group.
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    Do weekly water changes and check on your filter occasionally. So long as you preserve the tank's hygiene, you should have no problem keeping your fish healthy.


  • When adding your fish into a new tank, hold the bag in the tank for about 20 minutes before releasing them into the water. This helps their temperatures stabilize.
  • If you are going to use plants, make sure you choose hardy plants such as Java moss and Anacharis. Goldfish tend to nibble plants' leaves. Hardy plants are a very good idea, since they provide oxygen and small amounts of food for the goldfish.
  • Never put gravel in your tank which can stuck in your fish's throat. Pick gravel that is smaller or larger than your fish's throat.
  • Some types of goldfish are incompatible with other types. You should separate different species into four categories. Pond-hardy goldfish (common goldfish, shubunkin, comets), fancy goldfish (Orandas, black moors), extremely fancy goldfish (ranchu, egg fish, dorsal-less fish), etc. Pond hardy cannot be mixed with rare, fancy cannot be mixed with extremely fancy, etc. Find out the different types and only mix goldfish from their corresponding group.
  • Make sure to clean the tank regularly to prevent bacterial blossom.
  • When adding your fish let the bag float for about 15 minutes. Add some of the water from the tank so they can get used to the temperature. Let it float for another 15 minutes. Slowly release your fish.


  • Do not dump water from the fish store into your tank. This water could contain harmful organisms. Gently scoop the goldfish out, and the net into the water quickly. Let it swim out on its own.
  • Only use decorations meant for aquariums, and remember to boil rocks before adding them to the tank.
  • Water and electricity don't mix! Make drip loops with nearby cords so that no water from your tank gets into the socket.
  • Goldfish are cold water fish. Don't mix them with tropical fish! If your tank is set up properly for tropical fish, your goldfish will suffer (and vice versa).

Things You'll Need

  • Fish tank
  • Filter
  • Heater
  • Bubbler
  • Thermometer (only use thermometers meant for fish tanks)
  • Gravel
  • Water treated with water conditioner
  • Food, fishnet and decorations
  • Algae scrubber
  • Gravel vacuum or siphon

Article Info

Categories: Aquariums