Beginner's Guide

Why is Tap Water Not Safe For Fish? & How to Make It Safe?

In simple words, Tap water is not likely to be safe for your fish. Tap waters are specially treated with chemicals like chlorine or chloramine to kill bacteria and make water safe for humans. But in the context of cold-blooded animals like fish, water mixed with chlorine or chloramine can affect fish’s health crucially.

Elements that make Tap Water Not Safe for Fish

The main reason for Tap water not safe for the fish is the presence of Chlorine and Chloramine.


Chlorine is a very reactive chemical that is commonly used in tap water for making water safe for humans. But for cold-blooded animals like fish, tap water is a totally kind of punishment. Chlorine is a chemical that is used to kill different pathogens like bacteria, viruses, and protozoans in the water to make water drinkable for humans. But for your fish, it directly impacts the gills, mouth, and eyes.


Chloramine is the combination of chemicals like chlorine and ammonia, which is used in tap water for the assurance of safety. But in terms of fish, it is highly poisonous as it kills the necessary biofilter bacteria for the fish also. As a result, chloramine like chemical can lead your fish to death easily.

Does my Tap Water Contain Chlorine?

And the answer is Simply ‘Yes.’ If you are getting water from the city or municipality, the water will be mostly treated with chlorine. Chemicals like chlorine are treated in tap water just to kill the bacteria, protozoa, and germs to ensure safe water. But the treated tap water is almost a total hazard for the fish in your tank.

Is there any possible way to check the Chlorine level in a tank?

When there is a will, there is the way. You can surely check the level of Chlorine present in your tank. There are different kinds of test kits found in the market from which you can quickly check the chlorine level of your water and are inexpensive too. You can easily get those kinds of test kits from the local pet or fish stores. Dual Range Chlorine Test Kit, FAS-DPD Chlorine Test Kit, JNW Direct 7 in 1 Aquarium Test Strips, High range Chlorine Test Kit And DPD Free, Total and Combined Chlorine Test kit are typical chlorine test kits you can use.

How to Test Tap water For Fish in Tank?

For testing the tap water of the tank, there are many test kits available in the market. Some of the best Test Kits to test the tap water are:

    • Tetra Easystrips 6-in-1 Aquarium Test Strips,
    • API Freshwater Master Test Kit,
    • JNW Direct in 1 Aquarium Test Strips, A
    • PI Saltwater Master Test Kit,
    • General X Aquarium Test strips.

API Freshwater Master Test Kit

If you are searching for a good test kit, API Freshwater Master Test Kit is the right one for you. You can examine the tap water using this test kit regarding the level of nitrates, nitrites, pH, and ammonia in your Aquarium. It is very economical, and it comes with detailed instructions on how to use it properly.

Tetra EasyStrips 6 -in-1 Aquarium Test Strips

Tetra EasyStrips 6-in-1 Aquarium Test Strips is a test kit for testing water, which is well-known for its distinct and practical features. You can test the tap water using it within 60 seconds. It comes up with detailed instructions and features. And lastly, buying it won’t hurt your budget as it is economical.

JNW Direct 7 in 1 Aquarium Test Strips

This test kit measures a total of 7 distinct tests that consist of chlorine, pH, carbonates, hardness, nitrates, total alkalinity, and nitrates. It is easy to use and comes with 150 strips appropriate for a total of 150 tests. You can get the result of a sudden by dipping it and making comparisons with a big color chart that is mentioned in the product’s bottle. You will get proper instruction for its use.

API Saltwater Master Test Kit

It comes with one color measurement card, a total of six bottles of testing solutions. API Saltwater Master Test Kit only tests the four primary concerns of saltwater tank, specifically high pH range levels, nitrates, nitrites, and ammonia. You can easily find this one nearby your local or fish shop.

General X Aquarium Test strips

This test kit contains 150 individual strips for every 150 tests. It is one of the best test kits, which makes it easier to examine the water quality. It is cost-effective and a total time-saving kind of thing. You can easily use this test kid as it comes with step by step instructions and different aquarium care tips along with it.

Things to consider before using tap water for fish

These all kinds of test kits mainly focus on examining the water quality of tap based on its pH, kH, gH, Heavy Metals, Ammonia, Nitrite, Nitrate levels. So here the information you need to know about:

Suitable ranges of ph, kH,gH, Nitrate, Nitrite, ammonia, heavy metals, and their testing tips

pH value

As you have already read in science, the neutral pH value is 7.0 through. For the most variety of tropical fish, a pH of 6.8 – 7.2 is considered ideal. Goldfish prefer a pH of 7.5. Amazonian fish like neon tetras and angelfish prefer a pH value of around 6.5 to 6.7. Mollies and swordtails thrive at a pH value of about 7.2 to 7.5. Most African cichlids need a water environment with a pH value of 8.2 or higher. A pH value between 8.2 to 8.5 is ideal for saltwater fishes.

The pH should be tested weekly. For most of pH measuring equipment, the pH value below 6.0 will read 6.0, and any pH value above 9.0 will read 9.0. Make sure you use the freshwater color chart when testing pH for freshwater, and you use the saltwater chart when testing saltwater.

KH (Carbonate hardness)

Carbonate hardness is a way to measure the amount of the presence of carbonate, bicarbonate in water. Carbonate hardness is a crucial factor in maintaining a stable environment for fish to live.

4-8kh is the suitable value of KH for freshwater fish. But for adding fish to the water, you need to be concern about their appropriate kH value like 40 2.2º for Discus, arowanas, elephant nose, neons, cardinals, live plants,80 4.5º for Most tropical fish, including angelfish, tetras, botia, community aquariums, live plants,120 6.7º for Most tropical fish, including mollies, guppies, swordtail, cichlids, goldfish.

It reads from 0 – 240 ppm (mg/L) in freshwater. This test measures KH in ppm (mg/L). If you want to convert ppm to German Degrees, divide the reading by 17.9. Carbonate and Bicarbonate ions are present in l in spring water. The KH of tap water varies on the source of water and what kind of treatment it has gone through.

GH (General hardness)

GH generally means general hardness. For much freshwater fish, the ideal GH value is 4-12 GH and 12-20 GH for African Cichlid. Ideal GH value varies within the species of fish like 30 1.7º for Discus, arowanas, neons, elephant nose, cardinals, live plant, 60

3.4º for most tropical fish, including angelfish, tetras, botia, community aquariums, live plants

GH test reads from 0 – 180 parts per million (ppm) in freshwater. (ppm is equivalent to mg/L.) To convert ppm to German Degrees, divide it with 17.9. It is crucial to examine the GH from time to time. Some tap water has a low GH, while others have a high GH level. You cannot use this test cannot be in saltwater because the Calcium and Magnesium ion concentrations in saltwater are above the range of the test.

Nitrate and Nitrite

Nitrite in the aquarium water creates problems with fish respiration, and high levels of nitrite lead to fish death often. Even a little amount of nitrite causes fish stress by affecting the respiratory system.

A high nitrate level indicates the presence of fish waste and organic compounds, causing poor water quality and contributing to the likelihood of fish disease. High levels of nitrate also provide a nitrogen source that can enhance algal blooms (green water). Many aquarist researchers believe that maintaining a low level of nitrate improves the health of fish directly or indirectly.

Nitrite and nitrate should be tested once a week in order to make sure that the aquarium condition is well maintained. This test kit reads total Nitrite and total Nitrate in parts per million (ppm), which are equivalent to milligrams per liter (mg/L). .Nitrite reads from 0 – 10 ppm, whereas nitrate reads from 0 – 200 ppm in a simple word.

Heavy metals

Heavy metals like copper and iron are somehow beneficial for your fish, but other metals like lead and mercury are not so good for your fish. Somehow you can remove unbeneficial metals by using a reverse osmosis system. You can easily get a test kit from the nearest local fish shop.


There should be no amount of ammonia in your aquarium tank. A little amount of ammonia present in your tank drastically impacts your fish. Ammonia can lead your fish to death with no shadow of a doubt.

But there are test kits like Seachem ammonia alert from which you can know the level of ammonia present in your tank. A proper aquarium filter also helps to eliminate ammonia like chemicals from the Aquarium.

How many ways are there to make tap water safe for the fish?

There are mainly two ways to make tap water safe for fish. One is the Natural method, and another is by using certain chemicals. There is a wide range of products on the market that you can use. The growth in online shopping has made it possible and easy for you to do so. You can make your tap water safe either naturally or artificially, as per the requirement.

Natural home remedies

If you don’t want to go through chemical options, you can make tap water safe naturally also. You can use preconditioned water from the nearest fish shop. If you’re going to lower the pH level naturally, you can introduce C02 and add some decorative driftwood in your Aquarium. To maintain the kH value, you can use baking soda and other minerals as well. To maintain ammonia, you can add plants and a proper aquarium filter. And to raise high naturally, you can try the crushed limestone. Besides this, there are two more natural ways to make tap water safe for fish.


You can let the tap water sit for 24-48 hours to let the chlorine evaporate. You can add an air stone or filter to stimulate the evaporation process as well. But using this method, you can only eliminate chlorine, not chloramine from tap water. So it is still risky in a different dimensional altogether.

Using RO DI Water filters for Aquarium

Using reverse osmosis(RO) Deionization(DI) water filtration systems is a very natural way to make your tap water safe. There is a wide range of varieties for filters that you can use to get rid of many fish health hazard issues. An activated charcoal filter is one of the best filters you can use to eliminate the level of chlorine.


Chlorine is the most harmful chemical that harms fish. To maintain it, you need to let tap water sit for 24 hours for the chlorine to evaporate. You can add an aerator to your water to speed up the evaporation process. If you still have a problem with evaporation, you can use API’s tap water conditioner. TAP WATER CONDITIONER is a chemical that instantly removes chlorine and neutralizes chloramines particles from your tap water.

Chemical route

There are different chemicals you can use to make your tap water safe. One of the highly recommended and best conditioners you can use is API’s stress coat. It creates a synthetic coating as it works as a protective shield for your fish. Quick Start, Stress Zyme, Stress Coat are the most popular and highly recommended API products for treating the tap water.

How to Naturally Clean Tap Water / How to dechlorinate aquarium water?

There is a wide range of varieties of chemicals for the dechlorination of water. If you don’t want to use the harsh chemical on your Aquarium, you can surely go through the natural ways. So, let’s have a look at followings:

Boiling the water

Boiling the water for dechlorinating the aquarium water is the best way you to go for if you are looking to remove chlorine naturally. It is a fast, economical, and easy way to remove harmful chemicals like chlorine from the water. Just remember to keep the boiled water out for 20 minutes(let it cool), and then you can add water to the tank. As you don’t want your fish to end up with high-temperature water.

Let it sit

To dechlorinate the water naturally, letting it sit way is also the best, easy, and economical way to do it. Keep the water for at least 24 hours before adding it into the Aquarium helps you to get rid of chlorine. If there is a presence of sunlight, then the process will be faster. Your tap water contains chemicals like chlorine and chloramine. This method can dechlorinate the present chlorine, but for removing chloramine, you have to go through another intensive one.

Using Ultraviolet light

Using Ultraviolet light is a very effective way of dechlorinating the water naturally. It removes chlorine and chloramine as well. If you have saltwater, you may have a UV sterilizer as well. Though buying the new UV sterilizer won’t cost you high. Up to the time, your Sterilizer can work with different parameters; you don’t need to worry about the specs of fish. It is one of the best and reliable ways for you to dechlorinate aquarium water.

Carbon filter

Using the carbon filter for dechlorinating the aquarium water is a bit costly for you. Though using a carbon filter in your Aquarium is the best tool as it removes chlorine, chloramine, and other compounds easily. These kinds of carbon filters which can be fit in the fish tank come out of your faucet, and there are others also which can be installed directly during plumbing. It ensures the water of carbon filtered.

Treating with Vitamin C

Vitamin C is an ascorbic acid which is very familiar to fish and which can dechlorinate your aquarium water easily. It removes the present chlorine and chloramine like chemicals within the short interval of time. Simply adding one teaspoon to every gallon of water before adding it in the tank ensures neutralization for chemicals.

Dechlorinating water chemically

As tap water is treated with chlorine and chloramine, there is a need for you to use a water conditioner and dechlorinating agent for it. With the growth of online shopping, there are many best options for chemicals you can use for dechlorinating the water. There is the availability of many de-chlorinator and water conditioner in the market, but some of the best of it is:

Seachem Prime

Undoubtedly Seachem prime is one of the best de-chlorinator you can have. It just does not remove chlorine and chloramine, but it neutralizes the other heavy metal also. A big bonus is it eliminates the ammonia and nitrates too, which makes Seachem prime a total package. Just a drop of it can help you out hugely. As it is economical and a total package, Seachem Prime is the best option you can choose for dechlorinating the aquarium water.

Tetra AquaSafe PLUS Water Treatment

Tetra AquaSafe Plus is a good alternative among many de-chlorinator for treating the water. It removes the chlorine, chloramine in a matter of seconds. It is not so costly as one teaspoon of it can treat 100 gallons of water easily. AquaSafe PLUS even neutralizes the heavy metals and creates a protective layer for fish so far. It also helps in the biological filtration by increasing the beneficial bacteria in water.


It is another best dechlorinating option that has many features. One bottle of it can treat 600 gallons of water, which makes it economical so far. By using it, you can get rid of impacts on fish by chlorine and chloramine easily. Plus, it removes various causes

for gill irritation, tissue damage, and death so far, which ensures the safety of fish. You can get API tap water conditioners easily from the local fish shop and from online shopping.

Can Tap Water Kill Fish?

Yes, tap water surely kills fish with no shadow of a doubt. As tap water from the city or municipality has been treated with chlorine, ammonia, and chloramine like chemicals, it impacts fish health crucially. For humans, it is good so far, but for fish, it is a total disaster. Your fish cannot survive in the water with many chemicals like chlorine, ammonia, and so on. The presence of those chemicals in water surely gonna lead your fish to death.

How Long Does it take for tap water to be safe for fish?

Naturally, it takes like 24 hours for tap water to be safe for fish through dechlorination. But with the proper presence of sunlight, it takes up to 20 hours for the neutralization of harmful chemicals like chlorine present in water. But Keeping water for sitting doesn’t assure full safety for fish. It only removes chlorine, but there will be the presence of other chemicals in the water.

What do I need to do after I dechlorinate my tank?

After dechlorinating the tank, all you need to do is assuring the proper aquarium nitrogen cycle. It’s a phenomenon where beneficial bacteria become established and filter media, converting ammonia (toxic) to nitrite (poisonous), then nitrite to nitrates (non-toxic), which ensures fish safety. So that’s why maintaining proper nitrogen cycles is an important job to do after dechlorinating the tank.


Tap water from the city and municipality consists of different chemicals like chlorine, chloramine, and ammonia, and soon. For humans, it is fine so far, but for fish, it is a total disaster. So you need to be a bit concerned with it by examining the level of such chemicals from time to time using different test kits. As every problem has its solution, dechlorinating the water naturally or chemically can easily help you out. So there is no need to worry if you are a bit conscious about it.