Best Aquarium Water Conditioners – Review and Guide

Most of us remember as a kid being excited about getting your first goldfish. Do you recall if it died a short time later? This happens a lot because most parents don’t know they should treat the tap water.

Goldfish need the right kind of water just like any other type of fish. If you use tap water for any kind of aquarium, adding a water conditioner is extremely necessary! It could mean life or death for your fish.

It is important to test your aquarium water on a weekly basis to verify it has good quality. You also need to do a bi-weekly partial water change of not more than 25 percent to help reduce any toxic buildup, replenish the oxygen, and remove debris the filter missed.

The following water conditioners were selected as the top 10 to help you select one or more that would be best for your type of aquarium. If you have any questions, feel free to email us by filling out the form at the end of the reviews.

Aquarium Water Conditioners Reviews

Seachem Prime

If you are using tap water for your aquarium, you can treat up to 5,000 gallons with a 500-ml (about 2 cups) bottle of Seachem Prime®. It is a complete and concentrated conditioner for freshwater or saltwater. It will remove chlorine, chloramine, and it detoxifies ammonia, nitrite, and nitrate.

What’s nice about Seachem Prime® is that you also get very specific directions on how to measure by using the cap as each thread corresponds to about 1 ml each.

Seachem Prime® is not acidic, so the pH level isn’t affected. It will extract any heavy metals in the water to make it safe for animals and plants.

Prime® can be great for the goldfish if their immune system is down or if they get sick. Treating the water will leave a clean tank for all the tank dwellers while it gives you peace of mind. I’m glad to learn after all these years why my goldfish died.


  • Bottle cap is measuring cup
  • Won’t disturb the pH balance
  • It is great for beginners


  • Don’t use if it has black specs
  • Some bought online had a rancid smell

API Stress Coat

API has maintained its mission and goals of making products and solutions to help further the care of ornamental fish for more than 50 years.

API Stress Coat does wonders for fish who have scratched or broken their fins. It regenerates their damaged fish cells with Aloe Vera so they can have new ones.

It also instantly removes bad elements like chlorine and ammonia. Another really great thing it does is balance your fish’s electrolytes so they have a better immune system and can swim better.

Just add 1 tsp per 10 gallons of water to begin reducing stress, heal damaged tissue, and replace slime coating. It’s concentrated and a 16-ounce container can treat up to 9,600 gallons. Wow, I didn’t know it would last that long.


  • Formulated with Aloe Vera to protect and heal fish
  • Helps in reducing electrolyte loss in fish, making fish healthier
  • It lasts longer than other brands


  • Small tanks need special instructions as the included dosage instructions start with 20 gallons
  • Some complaints that it doesn’t get rid of the ammonia

API Conditioner for Tap Water

API conditioner is specifically made to cure your tap water of all the unhealthy compounds in it that can cause damages to your fish. Tap water can cause gills to be irritated or destroyed. It can even cause fish to die.

API conditioner will work instantly to make tap water safe for fish by neutralizing chlorine, chloramines and other chemicals or heavy metals. It will also keep any diseases brought by other fish under control.

You should use it when you change water and when adding water or fish. It is available from 1.25 oz to 64 oz bottles. It is very concentrated, so a single ounce is enough to treat up to 600 gallons. You can use to treat the aquarium water for both the saltwater and freshwater tanks.

API gives you a detailed dosage guide and instructions. The bottle also has instructions for how much to use to remove chlorine and other chemicals. You can use the cap to measure it accurately.


  • It has components that help heal injured fins
  • It has a detailed dosage guide
  • It comes in different size bottles


  • No directions for less than 20-gallon tanks
  • It has had complaints of a foamy film on top of the water

Tetra BettaSafe

Tetra has been in the water conditioning industry for over 35 years. That has made them one of the best in the market. BettaSafe does what the label says—keeps your “betta safe” from harmful chemicals.

It is an all-in-one water conditioner that works to keep your water safe and healthy for your betta fish. It detoxifies harmful ammonia in tap water, neutralizes chloramines and chlorine, heavy metals, plus it provides stress reducing slime.

BettaSafe has technology that gets all the heavy metals together so they can be removed by the filter easily. You can also use it in marine water or freshwater.

BettaSafe has a new feature that no other brand has. It is a blend of minerals that usually are lacking in tap water. It also has vitamins added to help the fish be healthier and more active.


  • It has components that help heal fin damage
  • Provides the slime coat for your betta
  • It has added minerals and vitamins


  • You need to calculate dosage if you have a small tank

Natural Rapport Conditioner

Natural Rapport Water Conditioner is a professional grade of conditioner and it’s the only all-in-one water conditioner that fish need for freshwater or saltwater aquariums.

It quickly removes harmful bacteria such as ammonia, nitrate, chlorine, chloramine, heavy metals, and more. Treating during water changes will help your fish thrive as it balances the pH.

Natural Rapport water conditioner also adds electrolytes and treats slime and stress coats. It is recommended for betta, exotics, or aqua live reefs. It is also safe and good for crustaceans and marine invertebrates.

With Natural Rapport there is no need to do separate steps or buy extra accessories and supplies. You also won’t need to buy chemical kits to treat stress or slime coats.


  • It has all-in-one components that help all types of fish
  • You can use it on saltwater, marine water or freshwater
  • It balances the pH, adds electrolytes, and treats slime and stress coats


  • A complaint that it didn’t neutralize ammonia
  • Complaint that it doesn’t work

Aqueon Conditioner for Tap Water

Aqueon Tap Water Conditioner neutralizes the chlorine and chloramines in tap water. Fish can be sensitive to new surroundings and this helps to reduce the stress on fish when they are moved to a new tank. It detoxifies heavy metals, ammonia and other elements.

Fish can also get their slime coat worn away from being moved in a net and the Aqueon helps restore the natural slime coat to skin and gills. It is formulated especially for smaller betta bowls that don’t get much filtering.

Aqueon is safe to add to fresh or saltwater aquariums but be sure to keep it away from children. Comes in 16-ounce bottles that are made in the USA.

Aqueon instantly makes tap water safe for fish and the cap can be used to measure how much is needed. You can go through this stuff fast especially when using for all my betta bowls.


  • Supplement for fish that have been stressed from being moved
  • Convenient dosage cap is included
  • Restores the natural slime coat


  • Complaint of receiving shipment with the cap leaking
  • Complaint that there was foam on top of water

Hikari Ultimate Water Conditioner

Hikari’s Ultimate is known as the world’s first water conditioner that is fully functional. After researching and testing thoroughly, Hikari has used their 140 years of experience to create magic in a bottle.

Everything you need is in one bottle to maintain a toxin-free environment for your aquatic friends. It neutralizes the chlorine in your tank and removes other toxic compounds like ammonia and copper.

Some conditioners have many additives that are not necessary, but the Ultimate has everything that is needed to keep your tank free of toxins and can be used in fresh or saltwater.

Hikari is great for new setups as it instantly ages water allowing you to enjoy your fish in action quicker without fear of the negative impact of toxins, heavy metals or nitrite. I had no idea you could age water.


  • It works fast!
  • They have various size bottles
  • Many claim that it works great


  • Complaint that it does not neutralize ammonia

Fluval Water Conditioner for Aquariums

Fluval Water Conditioner neutralizes chlorine, chloramine and undesirable metals in aquarium water to make your tap water safe for tropical fish. It is formulated with pure herbal extracts.

Fluval’s conditioner will make water safe for aquarium use by removing harmful waste and toxins as well as adding beneficial bacteria to bring it to the correct balance. The beneficial bacteria will break down the unsafe organic matter (i.e. leftover food, fish waste, decaying leaves, etc.), which gather on surfaces.

You will be amazed how it can prevent inflammation and other conditions that may result from your fish’s injuries. You will be able to see how it reduces stress in fish and how it coats scales and fins to protect your favorite fish against scrapes and cuts.

It is especially helpful for goldfish, cichlids and heavily populated aquariums where there is a greater amount of waste. Use in combination with Fluval Biological Enhancer to provide an ideal balance for use in new aquarium set-ups and regular maintenance.


  • Improves water for tropical fish
  • Help reduce stress especially in crowded tanks
  • Coats and protects scales and fins


  • Can get used up much faster

TankFirst Complete Aquarium Water Conditioner

There is no awful smell like with some other conditioners that smell horrible. TankFirst takes any smell out by using a natural additive that is very effective without any bad smell. Plus, you don’t have to worry about getting it measured perfectly. A little too much won’t hurt the fish.

It’s good to see that TankFirst knows that fish can smell too. If you use TankFirst’s Complete Conditioner and tell others, then they or their fish won’t have to suffer from those awful smells.

TankFirst makes tap water safe by removing chlorine and chloramines; plus, it removes toxic ammonia, nitrites, and detoxifies heavy metals. TankFirst’s conditioner is perfect for all freshwater, marine, saltwater, and reef aquariums.

This water conditioner is trusted for use with the most sensitive fish and it is the perfect choice for freshwater shrimp, betta, and live planted aquariums.


  • It has no awful smell like some others
  • Works in all kinds of water
  • Removes ammonia like others don’t do


  • It is a hassle opening the bottle
  • Not packaged good enough to avoid spillage

Instant Ocean Reef Salt Crystals

Instant Ocean Reef Salt is formulated specifically for use in reef aquariums. It contains elements in greater concentrations than those found in a natural ocean. If you have polyp stony corals or coralline algae, you will love how the extra calcium helps them grow.

If you have a reef aquarium, it will amaze you how Instant Ocean Reef Salt provides extra vitamins and vital nutrients to help your corals and other invertebrates grow and survive for a long time.

Be sure to NEVER mix salt in an aquarium containing any fish or other aquatic life. They should be removed until it is mixed well.

It also neutralizes traces of heavy metals often found in tap water. Maintain your reef aquarium and watch it flourish with Instant Ocean Reef Salt.


  • Contains essential elements in greater concentrations than natural ocean
  • Has extra calcium to help in the growth of stony coral and coralline algae
  • Neutralizes trace heavy metals that may be found in tap water


  • Contact with dry foam can cause skin to get irritated
  • Not safe to be handled by children


The most popular water conditioner is the first one listed above of Seachem Prime® but many of the other ones do a good job of turning tap water into water fit for a fish. The most important thing is that you use a water conditioner every time you add water to the tank.

It is a good idea to mix the conditioner with the new water before putting it in with the fish. It also helps to have a dosage guide so you can be sure that the amount you add is enough.

Please write us in the comments about your experience with these products or if you have any questions about anything that may not have been addressed in this article.

We wish you many peaceful moments with your aquatic friends.

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