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Can Goldfish Live In Tap Water? (6 Ways to Make it Safe)

Can Goldfish Live In Tap Water? (6 Ways to Make it Safe)

Many goldfish around the world have been sacrificed as practice pets for children around the globe. It is tragic, but it is quite a common phenomenon, and many adults pass it off as natural – that goldish do not have that long of a lifespan. This statement is untrue because when properly taken care of, goldfish can live up to 10-15 years when properly taken care of. 

The most commonly noted reason for their death is switching from store-bought water to water from the tap. This can prove fatal as goldfish can only live in tap water after it has gone through a cleansing process to remove dangerous chemicals and toxins. 

Read on to find out more about what you can do to help your fish survive longer.

How Long Can Goldfish Survive In Tap Water?

Goldfish cannot survive longer than a few minutes in untreated tap water. It will kill them almost instantly as it burns their lungs. If the pH level of your tap water is fine for a goldfish to survive (7.2-7.6), then it is safe. 

However, the chance of this happening is very less, and it is important that you never put your fish in untreated tap water. 

If in an emergency wherein keeping your goldfish in its aquarium for long will kill it for sure, you can switch to tap water for a minute or so. 

Even RO water from your filter is not good for your fish to be in as it is too filtered and deprived of its natural minerals. 

Both are not suitable for your goldfish, however, and you need to make sure your pet is back in its suited water almost immediately. Do not take any chances. 

What Type Of Water Do Goldfish Need?

Goldfish are sensitive, and your water needs to pass a certain criterion for it to be safe for your goldfish. The water in your aquarium should have the following traits.

  • Warm water with temperatures ranging between 20°C – 23°C (68 °F – 74°F) is ideal for keeping a goldfish. 
  • A pH level of 7.2 – 7.6
  • No ammonia
  • No nitrites
  • Nitrates lesser than 40ppm

goldfish in small tank

How Do You Keep Goldfish Alive In Tap Water?

Tap water is extremely harmful to your goldfish to be in. Getting store-bought water for goldfish from the pet store can be difficult each time you want to clean the tank. 

For these cases, there are ways in which you can utilize tap water to keep your goldfish. The following are a few solutions – but in case you are about to use any of them, remember always to have pH test kits. It is advisable to have them in general as fish owners. 

Note: Since you are using tap water, do the test below in the following article to determine the level of toxicity first. 

1. Let It Decontaminate In A Dish

Tap water can decontaminate on its own when left out long enough in the open. Take out the needed water for your aquarium and then set it out on a dish to let the chlorine evaporate on its own slowly. The process will take at least a minimum of 24 hours.

This can take a longer or shorter time, depending on your tap water. Sometimes it may be completely safe right out of the tap as well. This is why we need pH tests to determine the levels. 

Always do a pH test before letting your fish into your tank, even if your tap water comes out clean the first time, as it can be fatal for your pet. 

A plus side of this method is that water cools down to room temperature, which is ideal for your fish. 

2. Boiling

If you do not have a lot of time and cannot wait for a whole day, consider boiling your tap water instead to remove all germs. Boiling evaporates the chlorine and removes harmful bacteria that can cause skin diseases to your fish. 

The time you need to let the water boil depends on your amount. For a large amount, use a wider container for boiling. On average, 15 minutes should be enough to kill bacteria in 10 gallons of water. Always remember to let the water cool down to room temperature. 

3. Cleanse Using Water Conditioner

Water conditioners are equivalent to water softeners. They neutralize chlorine and ammonia and instantly break down chloramine from tap water. Add the conditioner before you fill your aquarium with tap water to let it cleanse first. 

They are also easy to use and relatively less expensive than installing filters. Some also help in supporting the protective slime coating of fish. The amount that needs to be added should be as per the product’s instructions. 

4. Use A Reverse Osmosis Unit

Using a reverse osmosis unit can be expensive but a great way to filter out tap water. It can be directly linked to your faucet to filter out harmful chemicals immediately. It also lowers the pH level of hard water and is a good option for cleaning aquariums. 

The pH of the tap water also depends on your area. Hence, if you are in areas where hard water is present, investing in a reverse osmosis unit is a good idea.

5. Use An Ultraviolet Light 

Using ultraviolet light or a sterilizer to dechlorinate tap water is an effective and easy way. Using an ultraviolet ray with a more than 93% transmitting rate can also help kill bacteria and viruses and prevent algae from gathering. 

The downside of this is that UV light can also kill beneficial bacteria. Around 30 minutes should be good enough to purify your water, but remember to do it without your fish inside. 

6. Use Water From Your Filter

Since goldfish mainly need clean water to survive in, you can use water from your filter as well. Filter water cannot be used directly since it is too purified and could lack beneficial bacteria. You need to regulate its minerals with a remineraliser or mix some water from your tap. 

You can use a pH test to determine when the water is balanced enough for your fish to go into. 

Note: Always test your pH level before putting your goldfish into your aquarium. 


How To Treat Tap Water For Goldfish?

There are two steps to treating water for goldfish. 

Step 1: Test How Bad The Tap Water Is

The first thing you need to do in the process of treating tap water for your goldfish is to test how bad your tap water is. For this, you need to buy a test kit that checks for ammonia, nitrite, and nitrate. You would also require to check for degassed pH. 

The following is how you test the pH level and check for harmful substances. Make sure you do this test before you get your fish to be on the careful side. 

  1. Leave your tap water sitting in a dish for 48 hours. 
  2. Keep an airstone in it. If you do not have one, you need to move the water every few hours.
  3. You can move the water by stirring it vigorously or scooping it with a  clean cup and then dropping it in the dish again. 
  4. Repeat this process every 2 hours while you are awake until 48 hours are up. 
  5. Next, do a pH test on the water in the dish and a test on water straight out of the tap.


The test from the water in the dish should not have any change on the paper. This indicates that the pH level is neutral (pH 7.0)

If the test from the tap water is any different from the test in the water in the dish, then the pH level is too high or low for your goldfish, and you must be extremely careful when changing water. 

You would either need to degas your water using rocks or aquarium cleaning systems before letting your fish in it.

Also Read: How to Lower pH in Aquarium (Causes & Quick Fix) 

Step 2: Treat The Tap Water

You can use the below-mentioned ways to treat tap water.

  • Water Conditioner

This is the best solution as a water conditioner acts almost instantly to remove all chlorine/chloramine and detoxifies all ammonia, nitrite, and nitrate. It works so well that many people add it to the water with the fish already inside it. A good conditioner is Seachem Prime. 

  • Use A Filter

There are many nitrate and nitrite absorbing filters that can immediately help cleanse your aquarium of its toxic substances. Some good examples of nitrite filters are Nitra-zorb and Purigen.

  • Use RO Water With Conditioner Water

An RO unit will be free of alkaline substances as well, but 100% RO water can filter the minerals out of the water. Hence, it is advised to use 75% RO water and 35% water treated with a conditioner. 

comet goldfish

Related Questions

Is It Okay To Put Fish In Tap Water?

It is okay to put fish in tap water if you take the proper procedures to clean it from all the toxins and neutralize the pH. 

How Long To Wait Before Tap Water Becomes Okay For Fish?

A minimum of 24-48 hours and longer if the pH test on the water is still not clear. 

Is There Any Fish That Can Live In Tap Water?

The most common aquarium pets that can live in tap water are as follows: guppies, molly fish, congo tetra fish, turquoise rainbow fish, golden wonder killifish, Odessa barbs, dwarf neon rainbowfish, pristella tetra fish, and platies fish.  

Final Thoughts

Goldfish are not pets that people usually get very attached to, as they would do for a cat or a dog. They do not interact much, nor can we understand what they feel. However, they still deserve the attention and care you would give other pet animals.

Hence, when taking care of your goldfish, at least make sure that the water they are kept in is as per their needs. When kept happy, you would notice how they appreciate it because they swim up to the people they like – and there is nothing more satisfying than seeing a typically plain pet show so much affection.