Best Water Conditioners For Freshwater Aquariums

Though you can’t see them, smell them, or taste them (and it’s not recommended to try), invisible assassins are lurking in your aquarium. The best aquarium water conditioners for freshwater aquariums can help reduce the risk of harming your fish by reducing the harmful elements.

These go under such names as chlorine, chloramine, and various heavy metals, and stem from a fishes very life source, its water! Read on to discover how to resolve this problem by using one of the best water conditioners for freshwater aquariums.

Fortunately, these chemicals and metals can be removed, and easily, from your aquariums water. You just simply use a water conditioner when adding tap water to your tank. Which water conditioner, however, is a little more difficult to decide, as there are so many to choose from. So here is a guide to help you make that decision including reviews of the top five.

Quick look at the 5 tested

What Is Water Conditioner?

Put simply, a water conditioner is a solution that removes or neutralizes chemicals and heavy metals from your aquarium water. It makes your water safe for your fish to live in, and in some cases relieves stress and protects them from gill and scale wounds.

Of course, water conditioner has not always been necessary. In fact, until chlorine was put into water it did not exist at all. Even then it was not an instant invention as chlorine was simple enough to eradicate. You could remove it by letting water sit for a period of time, or by boiling it.

Over time, nonetheless, sodium thiosulfate came along which instantly removed chlorine, and best of all was harmless to fish. However, this solution didn’t last long as water suppliers started to add ammonia. Ammonia plus chlorine equaled chloramine, another chemical harmful to fish, and ‘hey presto’ a new water conditioner was needed.

The new water conditioner that was launched took care of both the chlorine and chloramine, but developments didn’t stop there. Modern water conditioners can also remove heavy metals, control nitrates, and improve a fishes slime coat.

Why Is Tap Water Not Safe?

Supplied for the use of humans, tap water has to meet extremely stringent drinking water standards and generally does. This, however, means the addition of certain chemicals such as chlorine-based disinfectants which are harmful to fish. Exposing fish to such chemicals can damage delicate gills and skin surfaces, resulting in irritation, stress, and possibly even death.

On top of chlorine-based disinfectants, many water supplies also include other potentially harmful contaminants such as cadmium, copper, lead, and zinc. These are commonly known as heavy metals, and unfortunately fish are much more sensitive to them than humans. Even tiny amounts of heavy metals can be harmful and lead to gill damage, and in extreme cases death.

TOP 5 Aquarium Water Conditioners Tested & Reviewed

Tetra AquaSafe Plus Water Conditioner/Dechlorinator, 33.8-Ounce

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as of May 23, 2024 9:27 am


  • FOR FRESHWATER AND MARINE aquariumS: Tetra AquaSafe Plus works instantly to make tap water safe for fish.
  • ADVANCED FORMULA: Neutralizes or removes harmful chlorine, chloramines and heavy metals.
  • PROTECTS FISH: Enhances protective slime coat to help wounds heal.
  • CLEAR AND HEALTHY WATER: With natural biopolymers and essential vitamins and minerals.
  • WATER CONDITIONER: Use when setting up a new aquarium, with monthly partial water changes, or evaporation replacement.

Tetra Aquasafe Plus Water Conditioner

Tetra claims to ‘set the bar high in water care treatment and maintenance’, and it certainly lives up to those words with this product. Just one teaspoon per gallon of water neutralizes chlorine, chloramines, and heavy metals in seconds. It also provides a slime coat on your fish helping to not only heal but protect from abrasions. Aquasafe Plus also has the bonus of being suitable for both freshwater and saltwater fish.

After using this product for a while I found it to be incredibly easy to use with simple instructions. Be aware, however, that you need to measure the dose in the outer cap and not the inner. It also has a slight smell to it, but certainly not enough to put me off from using it. It has proved to be a reliable and exceptionally well-priced selection.

This has been our GOTO product for year! We have seen it used in many aquarium stores and pet stores around the world. It has been used and tested for over 20 years in the aquatic trade so you know it can be trusted.

Aqueon Central Aquatics Water Conditioner (16 fl oz)

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8 new from $4.08
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as of May 23, 2024 9:27 am


  • Use when filling aquarium with tap water, performing water changes or adding fish
  • Instantly makes tap water safe for fish
  • Supplement for fish that have been stressed, transported or netted
  • Detoxifies heavy metals, ammonia and other elements that are released from fish waste
  • Convenient dosage cap is included

Aqueon Tap Water Conditioner

You can’t go far wrong if you choose the Aqueon brand to condition your aquarium water. Not only does it neutralize chlorine and chloramines found in tap water but it can also help to reduce the stress of new fish you may add to your tank over time. As an added bonus Aqueon water conditioner also comes with a handy measuring cup so you’ll never make an error with your dosage.

I really have nothing bad to say about this product other than in a couple of my betta aquariums it left a foamy substance on the surface. This was easily removed, however, though not ideal I admit, and since it did everything it says on the tin I will certainly continue to use it.

Seachem Prime Fresh and Saltwater Conditioner - Chemical Remover and Detoxifier 500 ml

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11 new from $13.45
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as of May 23, 2024 9:27 am


  • POWERFUL TREATMENT: Seachem Prime is a complete and concentrated conditioner for both freshwater and saltwater fish tanks, working hard to remove chlorine and chloramine.
  • REMOVER: Seachem Prime immediately and permanently removes chlorine and chloramine, successfully allowing the bio filter to remove ammonia, nitrite, and nitrate while they are detoxified for 48 hours.
  • DETOXIFIER: Seachem Prime effectively detoxifies ammonia, nitrite, and heavy metals found in the tap water at typical concentration levels, providing a ideal environment for your betta, tetra, or other fish.
  • USE: Use 1 capful (5 mL) of Seachem Prime for each 200 L (50 US gallons) of new or replacement water. For best results, add Seachem Prime to new water first. For exceptionally high chloramine concentrations, a double dose may be used safely. For smaller volumes, use 2 drops per gallon.
  • SAFETY: In case of an emergency, the 5x dose of Seachem Prime may be used for both ammonia and nitrite. Use a ½ dose if the water temperature is > 30°C (86°F) and chlorine or ammonia levels are low.

Seachem Prime Fresh / Saltwater Conditioner

Prime is a complete and concentrated water conditioner that can be used for both fresh and saltwater aquariums. It works hard to immediately remove chlorine and chloramine. Being concentrated, the dosage is just one capful (5ml) for every 200 liters (50 US gallon) making it an economical choice. For aquariums with exceptionally high chloramine concentrations, a double dose can be safely used.

There is no doubting that this product is economical making it for most people an excellent buy. However, I found the stench of rotten eggs filling most of the rooms in my house, where I keep aquariums, a little too much to bear. I’m sure, nonetheless, since this product does exactly what it claims to do, that for some it will be ideal.

API TURTLE WATER CONDITIONER Water Conditioner 8-Ounce Bottle

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10 new from $6.76
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as of May 23, 2024 9:27 am


  • Contains one (1) API TURTLE WATER CONDITIONER Water Conditioner 8-Ounce Bottle
  • Made in the US
  • Package weight : 0.65 pounds
  • Package dimensions : 1.75 inches (H) x 1.75 inches (L) x 7.5 inches (W)

API Turtle Water Conditioner

As good water quality is key to a beautiful and healthy vivarium, it is essential you use a high-quality water conditioner for its inhabitants, and API Turtle is just that. It makes tap water safe by removing chlorine and chloramine and detoxifies heavy metals. It can also cut down on the amount of maintenance you may have to perform, leaving you more time to sit back and enjoy your vivarium.

Prior to using API, I had been cleaning my vivarium, and I mean deep cleaning it once a week. However, after using this, what I can only describe as wonderful, water conditioner that is no longer the case. I now only perform light cleaning on a weekly basis allowing me much more time to sit back and enjoy the aquariums inhabitant.

Fluval Water Conditioner for Aquariums, 16.9-Ounce

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5 new from $7.18
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as of May 23, 2024 9:27 am


  • Makes tap water safe for fish
  • Neutralizes chlorine, chloramines and heavy metals
  • Protects the sensitive mucous membrane of the fish
  • Patented stress reducing formula
  • For fresh and saltwater use

Hagen Fluval Water Conditioner

Handy, in that, it is suitable for both fresh and saltwater aquariums. Fluval water conditioner is also highly efficient and comprehensive. This conditioner removes all the chemicals you would wish it to do so, whilst also protecting scales and fins, and reducing stress. It comes with an easy to use measuring cup to ensure you give the correct dose. In addition, it comes in a great range of sizes making it suitable for aquariums large and small.

I used this product in a live planted Frontosa Cichlid aquarium which has struggled to bloom due to its grumpy inhabitant who loves to tear up plants and has to be removed, causing immense stress, during maintenance. On the plus side, this product seemed to help him calm down quicker on being placed back in his aquarium and aided plant growth. However, on the downside it also seemed to encourage algae growth within the tank which as any fishkeeper will know can be a problem.

Is It Suitable For Saltwater & Freshwater Aquariums?

Unless a water conditioner states that it is suitable for a saltwater aquarium you should never use it. This is due to the fact that water conditioners, in general, don’t remove chloramine and heavy metals – rather neutralizing them. This creates the problem that they remain in the water, meaning algae and cyanobacteria can still use them as a food source. That being said, a bottle of water conditioner can be a life-saver in an emergency, and it may be worth keeping a bottle to hand.

How To Use It

How you use a water conditioner will vary depending on the brand you choose – always check the container’s instructions. However, most brands will only differ slightly and will almost always suggest you mix water and conditioner before adding it to your tank. The amount you dose, hmm, well that’s still up for debate, with no definitive answer in sight.

On one side of the debate are those who believe that during a water change you should add water conditioner for the entire gallonage of your aquarium. However, this is challenged by the other side who claim you only need to dose for the amount of water you are changing. This, perhaps, though in no way certain to be correct, seems the most sensible answer as water already in the aquarium has already been treated.

cleaning a fish tank makes fish happy
Use after every water change

How Often Should I Use Aquarium Water Conditioner?

For those who are cycling their aquariums water conditioner should be used every few days when you perform the water changes that are required to ready your tank for fish. Otherwise, it should be used as often as you perform your aquarium maintenance. For most people, the use of water conditioners for freshwater aquariums will be weekly, perhaps fortnightly, but certainly always on a regular basis.

Types Of Water Conditioner

Water conditioners for freshwater aquariums can be divided into four different types although only one of them is commonly used by most fishkeepers.

Complete Water Conditioner

Absolutely the most popular and commonly used of the water conditioners for use in freshwater aquariums are complete, as the title suggests, does it all. It can:

  • Neutralize ammonia
  • Eliminate chlorine
  • Eliminate copper
  • Detoxify heavy metals
  • Protect slime coat
  • Buffer pH

and perhaps more!

The number of actions performed by a water conditioner depends entirely upon the brand.

Water Dechlorinator

This water conditioner can instantly remove chlorine but has no effect on ammonia and heavy metals. For this reason, it is not particularly popular, but you will still find it on many pet store shelves. Be warned, however, that if your tap water contains chloramine you should avoid this product. This is due to it, water de-chlorinator, allowing dangerous levels of ammonia to build up.

Chloramine Neutralizer

Chloramine neutralizer removes chlorine, breaks down chloramine, and neutralizes the ammonia in one of two possible ways. These are either by:

  • Binding the ammonia molecule, causing it to become harmless to fish


  • Converting the ammonia into ammonium, also harmless to your aquarium fish

It should also be noted that some brands may neutralize heavy metals, whilst others will not.

Reverse Osmosis Water Conditioner

This product isn’t technically a water conditioner, but since it is referred to as such by many fishkeepers we have decided to include it here.

As you probably know many reverse osmosis (RO) systems remove chlorine, chloramine, and other impurities found in tap water without the need for a water conditioner. However, they also remove some good stuff too. An RO water conditioner replaces these missing minerals such as calcium, potassium, sodium, and magnesium.

Winner of this review

It has to be Tetra Aquasafe for us. A tried and tested product for over 20 years. It has simple instructions to follow and is simple and effective.

It’s priced mid range compared to all the other products we looked at and the ones we tested but we believe it offers great value for money and if you purchase the 500ml bottle it will last you longer and be more cost-effective.

If you need more proof then read the 1200+ Amazon reviews.


  • What Do Freshwater Aquarium Water Conditioners Do? Put simply they remove chlorine and neutralizes chloramine in your aquarium’s water. Some also help to reduce stress in your fish and aid healing or protect them from wounds.
  • How Long Should Water Conditioner Sit? Generally, a good water conditioner should remove chlorine and chloramine within around 15 minutes or less. Some fishkeepers, however, allow their treated water to sit for up to 24 hours.
  • Do Goldfish Need A Water Conditioner? Yes, as tap water has at least chlorine added to it which can burn a Goldfish’s gills.
  • What Happens If I Put Too Much Water Conditioner In My Fish Tank? Nothing, though you can over condition your water, it’s really hard to do. In fact, you would probably need to pour an entire bottleful into your tank before you’d see any adverse effects.

Conclusion: 5 Best Water Conditioners For Freshwater Aquariums

When it comes to water conditioners for freshwater aquariums, one thing is for sure, and that would be that it is a product essential to the fishkeeping hobby. It not only helps to keep your water habitable for fish but also can protect them from injury and stress.

As to which brand of water conditioner you should choose to use, the choice is really yours. All the brands that we have selected here will do the job impressively. But the winner for us was TetraAquasafe 500ml.

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