Can You Use Tap Water for Fish?

Can You Use Tap Water for Fish | Ways to Make Tap Water Safe

Keeping fish at your home aquarium needs lots of effort to ensure a safe environment for the health of these small aquatic creatures. It also requires careful consideration of living conditions. Even a few minor alterations can lead to serious health issues or even cause the death of the fish.

So, can you use tap water for fish? One of the most critical aspects to consider while nurturing a fish at home is the water in your aquarium. But is tap water safe for a fish tank?

Regular tap water is okay for filling the fish tank, provided you make it safe by getting rid of chlorine.

If you live in the city or municipality, there is a higher chance that the water you get is treated with chlorine or fluoride. And although these chemicals are added to make water safer and better for human consumption, they may be toxic to your new fish. Also, if you get water from a well, there are many other potentially harmful elements (to fish) in that tap water.

Can You Use Tap Water for Fish?

school of assorted-color fish
Aquarium fish

The easiest method to dechlorinate tap water is using a water conditioner or dechlorinate. These will instantly remove chlorine from your water. However, if you don’t want to use any chemicals in your fish tank, there are other ways to eliminate chlorine.

Here are a few ways to make tap water safe for fish without conditioner.

1. Let the Water Sit for 24 Hours

One great way of getting rid of chlorine in the water before putting your fish in it is by off-gassing. Off-gassing is a chlorine removal process that involves putting the water in a vessel or open bowl and leaving it there undisturbed.

Most of the chlorine present in the water will naturally escape into the environment. Usually, the process takes 24 hours, and after that, your water is safe to use in your aquarium.

2. Boil and Cool the Water

This is the most effective, safe, and less costly way of making water safe for your fish tank. That’s because it’s fast and easy to manage, and literally, anyone can do it.

When you boil water, aeration will occur, and when this process combines with the heat, chlorine is easily eliminated from the water.

It’s is also important to note that boiling also eliminates chloramine, a chemical similar to chlorine, though it has no enduring effect on water.

Put water in a clean pot and heat it for about 15-20 minutes. Once the boiling process is over, remove the pot from the heat and let the water cool before pouring it into your fish tank.

See also: Is a 30 gallon fish tank good?

3. Use a Reverse Osmosis (RO) or Carbon Filter

Reverse Osmosis is a water purification method that involves removing the H2O water molecules to a separate water tank. The process usually involves forcing the water via a semipermeable membrane. All impurities are left behind during this process, usually in a Reverse Osmosis filter.

Reverse Osmosis filtration is also used to get rid of salt from water.

A Carbon filter is similar to the RO, but the only difference is that the water is pressured using a pump through a mass of carbon. This carbon will naturally absorb all kinds of harmful chemicals and substances, including chlorine.

silhouette of people looking at auqrium
Large aquarium

4. Use UV Light

A UV sterilizer is another excellent tool for dechlorinating tap water to make it safe for the fish tank.

When you bombard the water with UV rays, a reaction will occur, and the chlorine in the water will be neutralized.

The time frame in which this can happen depends mostly on the water volume you want to clean from chlorine. It’s best to do it in steps of 10 gallons at a time. This way, you can ensure that chlorine completely leaves the water.

While these sterilizers are most effective at dechlorinating water for the aquarium, they can also be used for the fish tank itself.

See also: How to sterilize aquarium equipment

5. Vitamin C Treatment

Besides being good for the common cold and flu, vitamin C can eliminate chlorine and chloramine from your water. However, when used for water treatment, vitamin C usually comes in the form of ascorbic acid.

Simply add a teaspoon of vitamin C (ascorbic acid) to each gallon of tap water you are planning to use. It will neutralize both the chlorine and chloramine in the water within a short period. Using vitamin C might affect the pH levels of the water, so consult a professional at your pet store if you need any help.

Nevertheless, this method is quite efficient, and you can also use it to dechlorinate a bath, hot tub, and even a pool.

See also: What do fish need to survive in a tank

FAQs About Water for Fish

Is Tap Water Bad for My Fish?

Some tap water contains high levels of magnesium or iron, while others may contain trace amounts of asbestos or ammonia, which can be dangerous on delicate fish.

Another problem with using city or municipality tap water for an aquarium is that it usually contains chlorine, which most public water facilities use as a decontaminant.

While it helps kill harmful bacteria, chlorine is toxic to fish and can even kill good bacteria. Chlorinated fish tank water will kill useful bacteria that collect on your aquarium filter to break down the toxic nitrite and ammonia found in fish waste.

What is the Best Water to Use for an Aquarium?

Tap water is undoubtedly the best water for the fish tank. However, it’s vital to ensure your tap water is free from toxic chemicals. Experts recommend using adequate conditioners to maintain the quality of fish tank water.

You can also use well water for your aquarium, but it’s important to take a good hard look at the hardness of the water. The underground well water usually contains many dissolved minerals that can cause harm to fish health. Only soft water should be used for a fish tank.

How Long Can Fish Survive in Tap Water?

Fish can survive in untreated tap water for only a few hours. The chlorine in the water will eventually kill the fish. If you have to use tap water in your fish tank, you must dechlorinate it beforehand.

Generally, tap water is perfectly safe for your fish. However, before filling your aquarium with tap water or even thinking about purchasing a fish, make sure you dechlorinate the water to get rid of chlorine.

Chlorine is quite harmful to fish and can cause burn on the fish’s body, making it susceptible to diseases or even death.


Florida Department of Agriculture and Consumer Services: Aquarium Water Quality: Sources of Water

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