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What Kind of Water Do Goldfish Need? Facts & FAQ (With Infographic)

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By Lindsey Stanton

ryukin goldfish in tank

Keeping a goldfish is about as simple as it gets. What kind of water do goldfish need? Can you use bottled, tap, or well water? Goldfish need clean water with average parameters, nothing too special or extreme at all. Let’s talk about your goldfish’s tank water requirements.

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Ideal Water Parameters for Goldfish

Let’s quickly go over what kind of water your goldfish needs, particularly in terms of the pH level, water hardness, and temperature.

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The water temperature for goldfish should be between 68° to 74° F.

pH Level

The pH level for goldfish water should be between 7.0 and 8.4.

Water Hardness

The water hardness level for goldfish, measured in GH (general hardness), should be between 200 and 400 ppm.

A good filter should be used in order to keep the water as clean as possible. The lower the levels of ammonia and nitrate in the water, the better, with absolutely none being the best.

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Can I Use Bottled Water for My Goldfish?

Yes, as long as it is natural water, there is no reason why you should not be able to use bottled water for your goldfish. Bottled water is generally filtered and treated to remove as many contaminants as possible. That said, make sure that the bottled water in question contains no chemical additives, especially not chlorine.

Natural spring water may actually contain minerals that goldfish need. On the other hand, if you have a very large tank, using bottled water to fill it up and refill it when you do water changes is going to end up being costly. On a side note, measure the pH level of the bottled water before using it, making sure that it is within the acceptable range.

Can I Use Well Water for Goldfish?

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In some cases, if you live out in the country and your well water is pure, you may be able to use it for goldfish tanks. However, in most cases, it is probably not a good idea to do so since well water directly from the source will not be pure enough to sustain a goldfish’s health. Well water often contains heavy metals and chlorine, which are deadly to fish even in small quantities.

It may also have fertilizers, bacteria, parasites, and other contaminants, along with heavy doses of natural minerals. If you are going to use well water, it needs to be clean and pure, free of chemicals and chlorine, and the pH needs to be acceptable.

If you need help getting the water quality in your aquarium just right for your goldfish family, or just want to learn more on the subject (and more!), we recommend that you check out our best-selling book, The Truth About Goldfish.

The Truth About Goldfish New Edition

It covers everything from water conditioners to nitrates/nitrites to tank maintenance and full access to our essential fishkeeping medicine cabinet!

How Do You Make Tap Water Safe for Goldfish?

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The real threat with using tap water for fish tanks is that for the most part, if you are connected to a local water supply, it will contain either chlorine or chloramine. Now, chlorine is the less problematic of the two, as you can simply let tap water sit out in the open for 24 hours and the chlorine will evaporate into the air. However, in many places, a stronger version is used to purify water, known as chloramine. Chloramine, unlike chlorine, will not dissipate into the air simply from letting the water sit.

Therefore, if you are unsure about whether or not your water contains chlorine or chloramine, or maybe both, it is a good idea to purchase a chlorine-removing agent. These can be bought online or at pet stores. Make sure to follow the instructions on the bottle. Also, before adding any tap water to any fish tank, make sure that you have tested for pH and adjusted it, if necessary.

How Long Do You Have to Let Water Sit Before Adding Goldfish?

As mentioned above, if the water contains only chlorine, and you are not using a chlorine treating agent to remove it from the water, letting the tap water sit for 24 hours should be enough, although you can tack a few hours on to that if you want to be safe.

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How to Change Goldfish Water

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Changing the water in your goldfish tank is very easy, and it takes only a few steps, so let’s go over these right now.

How to change water:
  • Get a decent aquarium vacuum to clean the gravel or sand substrate.
  • Get a bucket ready. This will hold the old water you are taking out of the tank.
  • Turn off any electronic equipment, such as air pumps, filters, and lights.
  • Stick one end of the vacuum (the suction end) into the tank, and the other end (the hose end) into the bucket. Switch the vacuum on or manually pump out old water into the bucket while also sucking up some debris.
  • Keep vacuuming out waste and water until you have removed roughly one-third or 30% of the water in the tank. Do not remove more than one-third of the water during any given water change, as this will remove too much of the beneficial bacteria in the tank and will put your goldfish at risk.
  • While you are at it, take the filter sponges and rinse them out in the water you removed from the tank, not in the tap water.
  • Insert the sponges back into the filter and put the filter back into the tank.
  • Now, fill up the bucket with as much tap water as you removed from the goldfish tank. Be sure to let it sit for 24 hours to allow the chlorine to dissipate, or if you choose, use a treatment agent to remove the chlorine. At any rate, you want to allow the water to reach room temperature.
  • Slowly and gently pour the treated water into the tank. Do this very slowly because you don’t want to give your fish a shock.

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As you can see, it’s not hard to change the water in your goldfish tank. Just be careful; ensure that it’s at the right temperature and pH level, and be sure it doesn’t contain chlorine. That’s about it!

Featured Image Credit: Moo teaforthree, Shutterstock

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