Will My Fish Die If I Put Them in Tap Water? You Need a Dechlorinator…

will tapwater kill fish

When you first start an aquarium, one of the first questions you will ask is – will my fish die if I put them in tap water?

The Ultimate Guide To Saltwater Fish…

Well, this depends on a number of factors, the occurrence of chlorine in tap water is one of them.

Your fish may die if you put them in tap water because tap water is known to contain chlorine, which is meant to kill the germs in the water. Tap water with a high concentration of chlorine will kill your fish. On the other hand, tap water with a low concentration of chlorine is less fatal, but is still very dangerous, as it will severely hurt your fish.

Chlorine concentration that’s as small as 2-3 ppm can be fatal to your fish.

Other factors that can determine the survival of your fish in tap water include the pH levels, hardness of the water as well as temperature change (which may be different from their previous habitat).

The species of fish you’re putting in the tap water will also determine whether they will die in tap water.

Freshwater fish can survive in tap water because the water has enough oxygen and minerals. However, saltwater fish may not do so well in the same surroundings, this is because they prefer more alkaline water. This all still depends on the amount of chlorine present in the water.

Fish species that prefer slightly acidic waters can also survive in tap water, although you have to introduce them to the water slowly.

Before you put them in a tank filled with tap water, keep them in a transparent plastic bag first, then add a little bit of water to the bag.

Leave it for about 20 minutes, then place the fish in the tap water-filled tank.

Before you put your fish in a tap water tank, make sure you dechlorinate it first. Even after dechlorination, your tank will still need some water plants.

There are some plants that are able to increase alkalinity in water, moss is one of them. This is good for saltwater fish.

Does Leaving Water Out Help Eliminate Chlorine?

Yes, it does, although this is the most time-consuming method of dechlorination. A major advantage of this method of dechlorination is that it is safe!

Leaving water to sit for at least 24 hours should do the trick. During this time frame, most of the chlorine in the water must have evaporated.

The dechlorination process can be sped up though, you can use a conditioner or de-chlorinator for this.

Unlike leaving the water to sit out for a day, the use of dechlorinators and conditioners can remove 100% of the chlorine in the water.

Use of Water Softener To Remove Chlorine From Tap Water

On its own, a water softener cannot remove chlorine from tap water, although it can remove iron, magnesium and calcium.

However, water softeners can remove the chlorine if used with the right water filter.

Using water softeners with Granulated Active Carbon (GAC) is an effective way of eliminating chlorine from tap water.

Is Boiling Water an Alternative?

You must have wondered if boiling water can eliminate chlorine from the tap water. Well, the answer is yes.

To achieve the best results, boil the water for about 20 minutes.

This method of removing chlorine is best suited for small quantities of water. For larger quantities, say 10-15 liters, you will need to boil the water in batches.

Heat reduces water’s ability to contain dissolved gasses, which makes boiling an excellent option for removing chlorine.

The major advantage of using the boiling method to remove chlorine is that it is very fast, it’s actually the fastest method known to man.

How Does Chlorine Affect Aquarium Fish?

As I mentioned earlier, chlorine can harm or kill your fish, but how?

Below are the effects of chlorine in tap water for fish

  • It causes breathing difficulties in fish
  • It reduces their ability to breed
  • Stunted growth

How To Make Tap Water Safe For Your Fish

Usually, tap water includes chlorine-based disinfectants for the purpose of killing germs. This makes tap water safe for humans to consume. However, the same chlorine-based disinfectant that makes tap water safe for humans makes it dangerous for fish.

This is why you must remove chlorine from tap water before you add it to the fish tank.

So, how do you remove chlorine from tap water?

I’ve already listed boiling and the use of water softeners as a means to remove chlorine from tap water. Now I’d like to recommend some of the best water conditioners you can use to make tap water safe for your fish.

Best Aquarium Water Conditioner

As long as you are using tap water for your fish tank, then it is a MUST that you use a water conditioner to remove chlorine from the water.

There are many brands and models of water conditioners available in the market. I will recommend a few which I consider the very best!

1. SeaChem Prime

Seachem Prime Fresh and Saltwater Conditioner

This water conditioner can detoxify nitrate and ammonia within a 48-hour time frame. During this time, the ammonia is broken down into ammonium, which is very harmless.

This is a great product for new aquariums, where the nitrogen cycle hasn’t been defined yet.

1ml of SeaChem Prime treats approximately 10 gallons of tap water.

2. Kordon Novaqua

This conditioner is capable of removing heavy metal from the water, as well as adding electrolytes.

It also aids in nitrifying bacteria in the filter by forming a slime coat around the filter media.

1ml of Kordon Novaqua treats 2 gallons of water

3. Hikari Ultimate

This product can replace skin slime coat, and this helps reduce fish stress. It can also remove ammonia and detoxify nitrate.

Its ability to remove heavy metals, and add electrolytes to the water is another useful feature of this product.

1ml of Hikari Ultimate can treat about 2 gallons of water.


I trust this article has been able to answer your question – Will my fish die if I put them in tap water?

They will, especially if the chlorine levels are high.

Thankfully, there are means by which you can remove the chlorine from tap water for the well-being of your fish.

Good luck!

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