How To Remove Ammonia From A Fish Tank Naturally

Keeping up with the care of your fish tank is a task that can be exhausting and troublesome but rewarding for both your fish friends and you! One of the most prominent issues to look out for in a fish tank is ammonia.

Ammonia can cause health issues for your fish and even cost the lives of your finned friends. If you’re worried about the buildup of ammonia in your fish tank, knowing how to remove it is imperative!

Removing ammonia from a fish tank naturally can be achieved by changing the water in the tank, fixing the filtration issues your fish tank may have, and adding natural components like bacteria or plants to the fish tank.

In this article, we’ll go over what ammonia actually is, its causes, and the natural ways to remove it from the fish tank, as well as a few frequently asked questions on the topic.

What is Ammonia?

Ammonia is a waste buildup produced by your fish. When your fish eats, it metabolizes the protein in its food. That metabolized protein gets flushed out through your pet fish’s gills, not necessarily its feces or urine.

Even if your fish does not eat its food, ammonia can still build up in a fish tank. Organic matter like fish food can cause ammonia to form as it disintegrates into the water.

When ammonia has built up to high levels, fish can no longer eliminate the ammonia in their own bodies. That can stress your fish out, injure its gills and internal organs, and even lead to the fish’s death.

Most professional aquarium workers establish a goal to have no ammonia at all present in their fish’s environment. In light of this, it is important to remove the ammonia in your fish tank!

Group of a small Gold Barb fish in an Aquarium

What Causes Ammonia in Fish Tanks?

Here are a few reasons behind the accumulation of ammonia in your fish tank:

  1. Decayed Aquarium Plants
  2. Breathing Process of Fish
  3. Dying Algae
  4. Fish Waste
  5. Fish Food
  6. Unclean Filter Pads
  7. Dead Fish

Let’s take a deeper look into each of these reasons so you can decide how to properly remove the ammonia from your fish tank naturally.

1.   Decayed Aquarium Plants

When an aquarium plant is alive, it processes the ions that ammonia is made up of. However, when an aquarium plant dies, its organic matter decaying only contributes to the ammonia levels in the fish tank.

2.   Breathing Process of Fish

Even though ammonia production is technically started when a fish eats, it is the breathing process of the fish that distributes ammonia throughout the tank. When your fish has its meal, its digestive system breaks down the protein, and its liver produces ammonia instead. The ammonia actually helps the fish’s gills to ventilate but must be excreted as the fish breathes.

3.   Dying Algae

A little bit of algae is helpful in a fish tank because it can produce oxygen while getting rid of toxic chemicals like nitrogen. However, when algae die, the bacteria aiding in decomposition can boost your fish tank’s ammonia levels just like any other decaying organic material does.

4.   Fish Waste

Fish produce urine and feces just like any other animal. When you compare the ammonia levels coming out of a fish’s gills, the amount that comes out in their poop may seem small. However, fish poop is made of broken-down nitrogen, which becomes ammonia and can be harmful.

5.   Fish Food

Fish food is an organic material; otherwise, your fish wouldn’t be able to eat and digest it! Therefore, even if your fish doesn’t eat their dinner, the fish food does decay. After about a week, that decay releases ammonia into the tank.

6.   Unclean Filter Pads

Filters that are the right size for the fish tank they are installed in don’t need to be cleaned more than once every three months. However, if a filter pad is left longer than this, it will become dirty and unable to protect your tank from ammonia spikes.

7.   Dead Fish 

A live fish produces enough ammonia on its own through the digestive process, but a dead fish is even more dangerous when it comes to ammonia levels. A dead fish’s body releases significantly more ammonia all at once as it decomposes than a live fish produces naturally.

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Signs of High Ammonia Levels in Fish Tank

If you’re wondering how you’ll be able to tell that there are high ammonia levels in your fish tank, the list below can be helpful. Here are seven signs of high ammonia levels in your fish tank:

  1. Lethargic Fish
  2. Fish With Inflamed Gills
  3. Fish Gasping Near the Surface
  4. Fish Without an Appetite
  5. Fish With Inflamed Fins, Eyes, and Scales
  6. Dead Fish
  7. Test Kit Results Show High Ammonia

If you’re noticing any of the above signs in your fish tank, it’s possible it has high ammonia levels. Let’s take a closer look at each of these signs so you can be sure of what you’re noticing.

1.   Lethargic Fish

Ammonia levels that are too high affect everything your fish needs to survive. They become unable to breathe correctly, see clearly, and eat with their usual appetite. Therefore, if the ammonia in your fish tank is too high, expect to see your fish swimming slowly near the bottom of the tank.

2.   Fish With Inflamed Gills

Ammonia may be secreted through fish gills during the natural breathing process, but if the ammonia outside of the fish’s body, in the water, is too high, it makes the gills’ job harder. Therefore, if your ammonia levels are too high, your fish’s gills will appear swollen and red from the strain.

3.   Fish Gasping Near the Surface

Contrary to popular belief, fish do actually need oxygen to survive. Oxygen gas is dissolved into most water, and it is this dissolved oxygen that fish need to absorb into their bloodstream through the gills to breathe. Therefore, when ammonia levels are too high, your fish will look for the oxygen it can’t get at the surface of your tank and appear to gasp for air.

4.   Fish Without an Appetite

If you’ve noticed that your fish avoids the flakes of food you drop on them instead of eating, as usual, it is a common sign of high levels of ammonia. Simply put, if your fish is feeling too sick to eat, it is an indicator that the ammonia in their water is the problem.

5.   Fish With Inflamed Fins, Eyes, and Scales

One of the signs that ammonia levels have reached dangerous heights in your fish tanks actually shows up, visibly in the form of burns on your fish. If your fish’s fins are ragged, their eyes are cloudy, or their scales have disturbing red patches, they are being burned by ammonia.

6.   Dead Fish

Unfortunately, ammonia poisoning is often fatal in fish unless dealt with. If a fish cannot eat or breathe correctly for too long, it won’t survive. If you haven’t noticed the previous signs of ammonia affecting your fish, you may find a dead fish in your aquarium.

7.   Test Kit Results Show High Ammonia

One of the simplest ways to be sure ammonia levels are high in your fish tank is to test it. There are test kits, such as the API brand, which involve dipping a test strip into the water. Usually, these kits come with a color chart. If your testing strip turns a color indicated by the chart to mean “high levels of ammonia,” you’ll have your answer!

How to Remove Ammonia From Fish Tank Naturally

Now that you know what ammonia is and how to identify whether or not it is too high in your fish tank let’s go over a few ways to remove ammonia from the fish tank naturally.

  1. Partially Change the Water in the Fish Tank
  2. Cycle the Fish Tank
  3. Increase the Air Circulation in the Fish Tank
  4. Improve the Filtration in the Fish Tank
  5. Add and Care For Live Plants in the Fish Tank
  6. Move to a Larger Fish Tank
  7. Add Beneficial Bacteria to the Fish Tank

Let’s go over each of these methods for removing ammonia from a fish tank naturally so that you can decide which works best for your fish and your lifestyle!

1.   Partially Change the Water in the Fish Tank

Possibly the easiest way to lower the ammonia levels in a fish tank is to complete a partial change of the tank’s water. Replacing around thirty to fifty percent of the water in your tank can do wonders for diluting the ammonia that’s causing trouble.

To do this, take a clean bucket that has never been exposed to chemicals or soap and pour regular tap water inside. Dechlorinate this with either a dechlorinating chemical from your local pet store, or allow the water to sit overnight.

Then, simply turn off the light and filter in your aquarium and drain the correct amount with a hose before slowly pouring in the new, ammonia-free water. 

2.   Cycle the Fish Tank

Cycling your fish tank is the process of making sure there are living bacteria in your aquarium. If you’re new to owning an aquarium, you may not know that it actually needs some bacteria to keep a good level of control on the ammonia in your water.

Cycling a tank takes six to eight weeks and is usually performed after removing the fish from your tank. It simply means that you make sure there are plants and smaller fish like minnows and barbs in the highly-toxic water, creating good bacteria to combat ammonia levels.

After this is done, you can add your fish back into the tank, safe in an environment that will balance out the ammonia they naturally produce by breathing and digesting food! 

3.   Increase the Air Circulation in the Fish Tank

Increasing aeration, or the circulation of air and dissolved air through the water of your tank, is very helpful in lowering ammonia. This is because aeration allows ammonia, which is gas dissolved in water, to transfer back to the air and then out of the tank itself, where it can’t harm the fish.

To increase air circulation in the fish tank, you can either buy an air pump or a spray bar at your local pet store. Be sure that the tank is not covered with a lid when you engage in the air circulation process.

4.   Improve the Filtration in the Fish Tank

If your filter isn’t working properly, ammonia levels will rise no matter what else you do to neutralize them. Therefore, make sure the filter pad is clean. The filter itself may need to be replaced or unclogged.

 If this doesn’t improve things, it may be because your fish are producing ammonia faster than one filter can handle, so you need to add a second filter. 

Finally, improving your tank’s filtration can involve vacuuming the bottom of your tank and getting rid of dead plants and uneaten food. These can not only produce ammonia but make it more difficult for your filter to do its job.

5.   Add and Care For Live Plants in the Fish Tank

If you’re looking for a natural way to remove ammonia from your fish tank, a live plant is one of the best methods! Plants need plenty of nutrients to grow healthily and then tend to get these from the waste fish and uneaten food produce. 

In this way, live plants can actually act as an ammonia-level balancer. The plants get rid of the ammonia-producing materials so that you don’t have to, and they are provided with the nutrients they need. All the while, they are also producing dissolved oxygen for your fish. Everyone wins! 

Some of the most durable plants to combat high ammonia levels are java ferns and java moss.

6.   Move to a Larger Fish Tank

If too many fish are in too tight a space, then there simply won’t be enough water, plants, or filtration to handle the ammonia that they produce. Consider moving your fish tank’s contents into a bigger aquarium. This will promote better dilution and give your anti-ammonia components, like filters and plants, a fighting chance to do their work.

7.   Add Beneficial Bacteria to the Fish Tank

This option is best if you have a brand-new fish tank that is disturbingly high in ammonia. The reason behind this is probably that your new tank does not have the bacteria it needs to cycle through the water.

A few quick ways to add good bacteria, which will process the ammonia in the water, is by taking elements from an old aquarium and transferring them to the new one. For example, try adding gravel or even a used filter pad to the fish tank.

What Does Ammonia Do in the Aquarium?

There is one circumstance during cycling your tank in which some ammonia can actually be a good thing. The typical effects of ammonia in an aquarium are useful to know when dealing with your own fish tank. Check out the list below:

  1. Ammonia Comes Into Contact With Bacteria
  2. Ammonia Turns Into a Nitrite
  3. Nitrites Turn Into Nitrates
  4. Nitrates Are Absorbed by Plants
  5. Water is Safe for Fish

Here is a more detailed look at the effects of ammonia in the aquarium.

1.   Ammonia Comes Into Contact With Bacteria

When ammonia is first added to an aquarium (either by adding pure ammonia or letting fish food decay in a tank empty of fish), it comes into contact with bacteria. This beneficial bacteria comes from a used filter or components like old gravel at the bottom of the tank. The ammonia actually kickstarts the good bacteria, helping it to grow to a healthy level.

2.   Ammonia Turns Into a Nitrite

When good bacteria come into contact with ammonia, it transforms that ammonia into nitrates or NO2. This process is what gives good bacteria their energy, and living bacteria are good for the overall environment of your fish.

3.   Nitrites Turn Into Nitrates

Nitrites, or NO2, can be transformed into nitrates, otherwise known as NO3. NO3 is important because it is the kind of chemical that can actually be dissolved.

4.   Nitrates Are Absorbed By Plants

When ammonia has undergone the process of being transformed into nitrates, it not only provides energy to good bacteria in the tank but can be absorbed by plants and organic life healthily. This is a big difference from ammonia’s original, toxic form!

5.   Water is Safe For Fish

Once this nitrogen cycle, which started with ammonia, is complete, the water is safe for fish. When fish are added to an aquarium that has been put through the nitrogen cycle, the natural ammonia they release can be managed by the good bacteria. As long as factors like poor filtration and removal of excess waste are in place, the good bacteria will handle ammonia!

Frequently Asked Questions

Below are some frequently asked questions about the topic of ammonia and removing it from fish tanks!

What Is The Fastest Way To Remove Ammonia From A Fish Tank?

The fastest way to remove ammonia from a fish tank is to remove 50% of the water from the fish tank. Then, replace that water with safe, chlorine-free, ammonia-free water to dilute the harmful ammonia levels. Check out this link to learn more!

How Long Does It Take For Ammonia To Build Up In A Fish Tank?

According to this link, it can take ammonia thirty to forty-five days to build up in a fish tank during the natural cycling process. However, if ammonia levels are spiking, it can take only a few days to notice the harmful effects of the buildup in your fish.


In summary, ammonia levels are necessary to start the healthy nitrogen cycle in your fish tank. However, if they are present at high levels afterward, you’ll start to notice the toll it takes on your fish. 

If the fish in your tank are gasping at the surface, burned by the ammonia, or lethargic, it is time to naturally remove ammonia from your tank. The fastest way to do this is by diluting the ammonia levels: move everything into a larger tank or replace fifty percent of the water.

Other methods for how to remove ammonia from a fish tank naturally include cleaning the filter and making sure good bacteria is present through plants and used gravel. This way, your fish can be safe from the harmful effects of ammonia levels spiking!

About the author

Hey there! I'm Antonio, the passionate owner and chief editor of Betta Care Fish Guide. With over half a decade of hands-on experience, I've become your go-to expert for all things betta and tropical fish.

Over the past 5 years, I've not only kept bettas and other tropical fish but also connected with a diverse network of hobbyists, seasoned fishkeepers, and even veterinarians.

Now, I want to help other beginner fish keepers who had the same questions as me when they were just starting out! So they can save themselves a ton of time and keep their fish happy and healthy!