Is Rain Water Good for Goldfish? Will They Survive?

If you are considering keeping goldfish you might be wondering is rain water good for goldfish?

Will they survive or will they have issues? Is their anything you need to do for them?

Find out below

Is Rain Water Good for Goldfish

Yes, Rainwater can be beneficial for goldfish in certain circumstances, but there are some factors to consider. Here are a few points to keep in mind:

  • Purity and cleanliness: Rainwater, in its pure form, is generally safe for goldfish. However, it’s important to ensure that the rainwater you collect is clean and free from contaminants. If you live in an area with high levels of pollution or acid rain, it’s best to avoid using rainwater for your goldfish.
  • pH and mineral content: Rainwater is typically soft and acidic due to the natural presence of dissolved gases, such as carbon dioxide. Goldfish prefer a slightly alkaline pH range of around 7 to 8. If the rainwater is too acidic, it may require adjustments to bring it within the suitable range for goldfish.
  • Chlorine and other chemicals: Rainwater is generally free from chlorine, which can be found in tap water. Chlorine is harmful to fish and can be removed by using a water conditioner or letting the water sit out for a day or two to allow the chlorine to evaporate. If you’re using rainwater, you won’t need to worry about chlorine.
  • Nutrient deficiencies: Rainwater may lack essential minerals and nutrients that goldfish need for their overall health. Regularly providing a varied diet and supplementing their water with appropriate fish-safe mineral supplements can help compensate for any potential deficiencies.
  • Collection and storage: If you’re collecting rainwater for your goldfish, make sure to use a clean container or barrel that is free from contaminants. Avoid using containers that may have previously held chemicals or other harmful substances. Additionally, keep the collected rainwater covered to prevent debris, insects, or other pollutants from entering the container.

While rainwater can be used for goldfish, it’s generally recommended to combine rainwater with treated tap water or use a high-quality water conditioner to ensure the water parameters are suitable for your goldfish.

How Do You Treat Rain Water for Goldfish

Treating rainwater for goldfish involves several steps to ensure its suitability for their well-being. Here’s a guideline on how to treat rainwater for goldfish:

  1. Collection: Collect rainwater in a clean container or barrel. Ensure that the container is free from contaminants and has not been previously used for storing chemicals or harmful substances.
  2. Settling: Let the collected rainwater sit for a day or two to allow any debris or sediment to settle at the bottom of the container. This step helps to remove larger particles that may be present in the water.
  3. Filtration: After the settling period, use a fine mesh or filter to remove any remaining small particles or impurities from the water. This helps to improve the water’s clarity and cleanliness.
  4. pH adjustment: Test the pH level of the rainwater. If the pH is too low (acidic), you may need to raise it to a more suitable range for goldfish. Use a pH buffer or adjuster specifically designed for aquarium use to raise the pH if necessary. Follow the product instructions carefully and make gradual adjustments to avoid rapid pH swings.
  5. Mineral supplementation: Rainwater may lack essential minerals and nutrients that goldfish require for their health and well-being. Use a high-quality fish-safe mineral supplement designed for freshwater aquariums to replenish any deficiencies. Follow the recommended dosage instructions provided with the supplement.
  6. Water conditioning: While rainwater is generally free from chlorine, it’s still important to ensure the water is safe for your goldfish. If you live in an area where there is a chance of contaminants or pollutants entering the rainwater, it’s advisable to use a water conditioner to neutralize any potential harmful substances. This step is crucial for ensuring the water is safe for your goldfish.
  7. Testing and monitoring: Regularly test the treated rainwater for parameters such as pH, ammonia, nitrite, nitrate, and general hardness (GH) to maintain a stable and healthy aquatic environment. Test kits are available at pet stores and aquarium supply shops.

Can Goldfish Live In Tap Water

No, Tap water contains chemicals that are bad for your goldfish, for this reason goldfish can not live in untreated tap water.  You will need to treat the water with a water conditioner before adding your goldfish to the water.

Apart from treating the water with a conditioner there are other water conditions that you will need to consider for your goldfish.

Can Goldfish Live in tap water

What Water Is Best for Goldfish?

The best water for goldfish is generally clean, dechlorinated tap water that has been properly conditioned. Here are some key considerations for providing the best water for your goldfish:

  • Tap water: Most tap water can be suitable for goldfish if properly treated. However, it’s important to remove chlorine and chloramines from the water before adding it to your aquarium. You can use a water conditioner specifically formulated for aquarium use to neutralize these chemicals. Follow the instructions provided with the water conditioner to ensure proper dosage.
  • pH level: Goldfish prefer a slightly alkaline pH range of around 7 to 8. It’s recommended to maintain a stable pH within this range. Regularly test the pH level of your tap water or aquarium water and make adjustments if necessary using pH buffers or adjusters specifically designed for aquarium use.
  • Ammonia, nitrite, and nitrate levels: Goldfish are sensitive to ammonia and nitrite, which are toxic to them. The beneficial bacteria in your aquarium’s filter should convert ammonia to nitrite and then nitrite to nitrate, which is less harmful. Regularly test the water for ammonia, nitrite, and nitrate levels, and ensure they are within safe limits. Perform regular partial water changes to keep these levels in check.
  • Hardness and mineral content: Goldfish prefer moderately hard water with a balanced mineral content. Test the general hardness (GH) of your tap water to determine if it falls within the suitable range for goldfish. If the water is too soft or lacks essential minerals, you may need to consider adding mineral supplements specifically formulated for freshwater aquariums.
  • Temperature: Goldfish are adaptable to a wide temperature range but prefer cooler water compared to tropical fish. The optimal temperature for goldfish is usually between 68°F and 74°F (20°C to 23°C). Avoid drastic temperature fluctuations and provide a stable and suitable temperature for your goldfish.
  • Filtration and maintenance: A good filtration system is essential for maintaining water quality and removing waste and toxins. Regularly clean and maintain your aquarium’s filter according to the manufacturer’s instructions to ensure efficient water filtration.

Ideal Water Conditions For Goldfish

Apart from treated water goldfish will require the following water conditions to thrive in your aquarium

  • Temperature : Between 60° and 70°F
  • pH Level : Between 7.0 and 8.4
  • Water Change : Recommended to change 10% of water every week
  • Filter : A good filter will be required to get rid of the fish waste
  • Oxygen : Recommend to add an air pump to add oxygen to the water

Whilst the above conditions are ideal goldfish can live outside of these conditions but they will not thrive.

Water Conditions For Goldfish

How Do You Treat Tap Water for Goldfish?

You can treat tap water by using dechlorinators or water conditioners (Available to buy on Amazon)

All dechlorinators and water conditioners come with instructions, be sure to read them before using the product.

The instructions will usually be

  • Fill 2/3 of your tank
  • Pour dechlorinator / water conditioners into the water (Check instructions for amount to add)
  • Leave in for about 24hours
  • Water is now treated and ready for the fish

I also recommend that you use a water testing kit (Available to buy on Amazon) To check the parameters of the water before adding fish.

water testing kit

Can I Use Bottled or Distilled Water for my Goldfish?

A lot of people see this as the next best option after tap water.

Distilled or bottled water is equally as bad as tap water. This is because they increase the PH level of your tank.

This upsets the PH balance of your tank and creates an unhealthy environment for your goldfish.

Can You Use Rainwater In A Goldfish Aquarium?

Rain water will not contain the heavy metals found in tap water, so can goldfish live in rainwater?

You can use rain water in your goldfish tank, as long as the rain water is pure.  It is important to collect the rain water from a source where it did not come in contact with a metallic or calcium surface.

The rain water should also be added to your tank within 30 minutes of being collected.

Rain water will also have a lower pH level than your goldfish needs but this should not be an issue for them.

Rain water is also softer than tap water so you might need to add some aquarium salt (Available to buy on amazon) to harden the water

I also recommend that you use a water testing kit before adding any fish to rain water.

Rainwater In A Goldfish Aquarium

Can I Use Pre-Conditioned Water?

This is another safe alternative. As the name implies, water that comes pre-conditioned (already treated and ready to use).

Pre-conditioned water comes with important minerals for your tank.

These minerals create a healthy ecosystem for your goldfish. Another bonus of using pre-conditioned water is that some pre-conditioned water comes oxygenated, this greatly improves circulation in your fish tank.

Pre-conditioned water can be added directly to the fish tank.

Other Reasons Why You Shouldn’t Use Tap Water for Your Goldfish

Tap water contains heavy metals such as

  • Fluoride
  • Mercury
  • Copper
  • Zinc
  • Lead

Your goldfish is very sensitive to these metals. They could burn their gills and make it difficult to breathe.

Although your goldfish need little of some of these metals, too much concentration of them could cause permanent damage to your goldfish.

Since tap water is heavily concentrated with these metals, it is only wise to not use tap water for your goldfish.

Your goldfish will produce waste of which this waste contains ammonia and as previously mentioned, is toxic for your goldfish.

Other Water Condition Factors To Need To Consider

There are also other water conditions you need to consider which are

Water Quality

Always remember, water is everything to your goldfish. Your goldfish will be grateful to you if you ensure its water is safe.

We have already established the importance of dechlorinators (this improves water quality greatly), but it is also important to regularly test the PH level of your fish tank.

Water Filter

Goldfish produce a lot of waste. This waste contains ammonia. Without a good filtration system, ammonia can build up and cause heavy damage to your goldfish. Filters remove harmful substances from your tank. Fitting the right size of filters will go a long way to promoting a healthy environment for your goldfish.

Water Temperature

The water temperature favorable for your goldfish varies with seasons. During the summer, the temperature of the water should be between 20°C to 23°C, and winter, 10°C to 12°C. Ensure to install a tank heater as this regulates the temperature of your tank.

Changing Water for Your Goldfish

It is necessary to change around 10% of the water in your tank every week.  This reduces the level of toxic substances such as ammonia and nitrate.

It also clears out fish waste and oxygenates the water, making it all the more habitable for your goldfish.

Note: Always refill the tank with treated water.


Below are the frequently asked questions about this subject.

Can Goldfish Live In Tap Water Without A Filter? A Goldfish will be able to live in tap water with out a filter but this is not recommended.  A filter is required to keep the water clean in your tank and remove things such as fish waste.

How Long Does It Take Tap Water To Be Safe For Goldfish? If you want to use tap water for your goldfish you will need to apply a water conditioner and will need to wit 24 hours for it to treat the water.

Well Water For Goldfish? Tap water and well water contains heavy metals which are harmful to your goldfish.  You will need to add a water conditioner and wait 24 hours if you wish to keep goldfish in this water.

Can Goldfish Live In Filtered Water? A goldfish will be able to live in filtered water for a short amount of time.  It is recommended to treat the water with a water conditioner and also make sure the water is well filtered.

How Long Can Goldfish Live In Chlorinated Water? A goldfish will be able to live in chlorinated water for a short amount of time.  It is recommended to treat the water with a water conditioner and also make sure the water is well filtered.


For your goldfish to live a long, happy and healthy life, you must; provide it with the best quality of water available, and also the best filtration system; Develop the right hygienic practice by changing water routinely; Always use dechlorinated water. Remember the safer the water, the healthier and the longer the life of your goldfish.


Hello, I'm Jason. I'm the guy behind I volunteer at my local fish shop and I created this site to offer tips and advice on the fish I care for.