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How To Get Rid Of Ammonia In Fish Tank: Here’s 11 Ways

Do you want to know how to reduce ammonia in a fish tank? Do you want to know what are ammonia levels, and where does it come from? Are you looking for a guide to recognizing the signs that the aquarium has a high level of ammonia?

Ammonia NH3 is an invisible chemical, highly toxic to fish, that hides in all aquarium tanks and that if it is not checked regularly, will soon kill all the fish in the tank.

In healthy aquariums, nature takes care of ammonia, keeping the levels to 0 ppm (parts per million), so if ammonia levels are higher than zero, is crucial to find fast the cause of the problem and take measures to solve it because the lives of the fish depend on having the level is zero.

What causes high ammonia levels in the fish tanks?

Like all living creatures, fish produce organic waste, and these waste products decompound into ammonia NH3. In nature, the amount of water per fish is exceptionally high, and waste products become reduced to low concentrations.

Ammonia occurs naturally in every aquarium, but as the water ratio is lower, if the ammonia can’t be diluted and transformed, the levels can increase in a matter of hours.
The unnecessary waste generally comes from the fish breathing, uneaten fish food, fish waste, pieces of dead plants and algae, and dirty filter pads.

What causes high ammonia levels in the fish tanks?
What causes high ammonia levels in the fish tanks?

The tank should be checked regularly to remove the waste trapped with a net or with a deep cleaning of the gravel every two weeks.

As mentioned before, ammonia levels are generally caused by organic waste. But besides that, high levels are also associated with an elevated concentration of fish in a small aquarium, because in a small space the fish will create an excess of waste that cannot be processed quickly, causing an increase in the level of ammonia.

Poor filtration, not doing proper and regular maintenance, and the absence of nitrifying bacteria in your filter are also some of the reasons for the high levels. When ammonia levels exceed 0 ppm, starting with as little as 1 ppm the nitrate poisoning problems start.

Expert Tip: At low levels, the ammonia burns the gills of the fish, and at higher concentrations, the organs and brain of the fish are damaged, until killing them.

This progressive poisoning causes a lot of stress on the fish, and while some fish are more tolerant of high levels, that doesn’t mean they aren’t suffering.

Ammonia levels are difficult to detect with the naked eye because it is transparent, but changes in the color of the fish, lack of appetite, the appearance of diseases, are visible symptoms of stress in fish due to high levels of ammonia.

It is important to test levels often to keep the tank ecosystem healthy, as well as the fish.
In the market, you can find different kit options, which measure not only ammonia but also PH nitrites, and nitrates in an accurate way and that can be done in easy steps. This is a guide of ammonia levels in the fish tank:

  • Safe, from 0.001 to 0.02 mg/L
  • Alert, from 0.02 to 0.05 mg/L
  • Warning, from 0.05 to 0.2 mg/L
  • Toxic. from 0.2 to 0.5 mg/L
  • Dead, more than 0.5 mg/L

If after performing a test the levels are above zero, it is time to act to reduce them to zero, or as close to zero as possible.

“Cycling Your Tank” and “New Tank Syndrome”

The biological process that converts ammonia into relatively harmless compounds is called the nitrogen cycle. This conversion is carried out by numerous species of bacteria in particular. Nitrosomonas species, convert ammonia (NH3) to nitrite (N02-) and Nitrobacter species, which convert nitrite to nitrate (N03-).

Cycling Your Tank
Cycling Your Tank

The term “cycling the tank” therefore relates to the practice of establishing colonies in the filter bed that transform ammonia to nitrite and nitrates. Nitrifying bacteria species are present everywhere, so a short period of time before the bacteria will establish a colony, once you have a source of ammonia in the tank.

The most common way to do this is to put one or two inexpensive fish in your aquarium since fish waste contains the ammonia that bacteria live on. Some suggested species are common goldfish for cold water tanks, zebra danios and barbs for warmer tanks, and damselfish in marine systems.

During the cycling process, ammonia levels will rise and then suddenly drop as nitrite-forming bacteria take hold. This is because nitrate­forming bacteria do not begin to appear until nitrite is present in significant amounts.

Nitrite levels skyrocket as accumulated ammonia is converted and continues to rise as ammonia produced continually converts to nitrite. Once the nitrate-forming bacteria take hold, nitrite levels drop, nitrate levels rise, and the tank is fully cycled, with ammonia and nitrite levels equal to zero.

Compared to other types of bacteria, nitrifying bacteria grow slowly. This process normally takes around 2 to 6 weeks, but at temperatures below 70F, it can take longer to cycle a tank. To determine when the cycle is complete, all you need to do is check them with a test kit.

It is important to avoid putting fish in before the cycle is complete, as discussed, more fish will generate more ammonia, which increases stress on all fish and the likelihood of fish death.

Here are 11 ways to effectively lower ammonia levels to a safe and manageable level for the fish:

1. Improve tank filtration

The number one tool to lower ammonia levels is in the filters. The filter is a fundamental part of the nitrogen cycle, in particular the biological filtration aspect. Beneficial bacteria grow on the filter and help break down the ammonia into nitrite and nitrate.

All the causes that contribute to increased ammonia levels are also related to the size of the filter and its ability to handle the water volume in the tank.

If the filter is insufficient, all these factors together can lead to a problem in the aquarium, so many times, excessive levels of ammonia can almost always be attributed to a lack of proper filtration in the tank. Adjusting and having an adequate filter will therefore help to efficiently reduce the levels of ammonia.

2. Performing a partial water change

Performing a partial water change
Performing a partial water change

Doing a partial water change once a week, or more often depending on the condition of the tank, is a great way to reduce levels. To figure out that frequency, an effective way is to gently remove the gravel from the bottom of the tank, if there is a lot of residual matter floating, it is a sign that the water should be changed more often.

The normal thing in a healthy aquarium is to change approximately 30% of the total volume of water in the aquarium, but if the ammonia level is high, the water change can go up to 50% of the entire water in the tank.

To make the change, it is not always necessary to remove the fish from the aquarium, just make sure not to injure or scare them when pouring the new water. The water to be introduced must be allowed to stand overnight to dechlorinate. or it can be treated with a dechlorinating agent.

Once the change is going to be made, remove the proportional volume of water, disconnect the electrical devices, and clean the algae and dirt that has been created on the walls of the aquarium. It is also important that the hands are clean of any residue of soap or cream, which can irritate the fish.

3. Remove all residual organic matter that should not be in the aquarium.

The decomposition of organic matter, mentioned above, is a major factor that aggravates ammonia levels. The organic waste can be simply removed using net Dead plants and algae, as well as dead fish left in the aquarium for a long time, releasing large concentrations of ammonia.

It will be useful to lower ammonia levels and prevent them from rising, too often removing everything that is dead in the aquarium and leaving only live plants and fish.
Uneaten food, as well as fish waste, contribute significantly to ammonia levels when they break down.

Expert Tip: It is important to clean the filter of the aquarium since it could re-introduce accumulated organic matter into the water, but it’s not advisable to replace the filter pads as this could disturb the balance of beneficial bacteria in the water.

4. Decrease the frequency and portions with which the fish are fed.

The fish must continue to consume an adequate amount of food
The fish must continue to consume an adequate amount of food

If the fish leave a lot of food uneaten, this residue could be the reason why the ammonia levels in the tank are high, therefore by decreasing the amount of food available in the aquarium, you will drop the chances that ammonia levels will rise.

The fish must continue to consume an adequate amount of food, the indications of experts or veterinarians on the frequency and portions will be of great help to find the right balance to keep them healthy.

It is important to note that changing the fish’s eating habits will not lower ammonia levels that are already high, however, this will prevent them from peaking in the future after the water has been changed.

5. Introduce good bacteria

If the aquarium is new or the healthy bacterial colony of Nitrosomonas and Nitrobacter has decreased, due to the so-called “new aquarium syndrome”, high levels may appear as they help to decompound the ammonia, so the final compound can easily get out of the aquarium through water change.

The average time it takes for these little organisms to proliferate to the point where they can get rid of excessive levels of ammonia is between 3 to 6 weeks. There are many beneficial bacteria products that can be introduced into the aquarium to help keep the nutrients in the ideal ranges.

However, these products will not immediately reduce ammonia levels. Instead, adding good bacteria to the aquarium to help the nitrogen cycle process faster is a better choice. One simple way to add new bacteria is by introducing one or two new fish.

Depending on the temperature of the water and whether it is salty or fresh, the type of fish will change. Likewise, placing some old gravel in a new aquarium can help.

6. Check how many fish are in the aquarium

Fish need more space than is normally thought to be healthy and happy, therefore having too many fish-eating and creating waste in a small tank is detrimental to increasing ammonia levels. A large fish population can lead to ammonia buildup quickly.

To avoid this common mistake among beginners, it is again advisable to seek expert advice, to keep balance.

7. Lower the tank’s pH

Lowering the pH won’t remove the ammonia, but it does make it less dangerous, and it is a quick fix if it’s not possible to change the water right away, non-ionized ammonia NH3 is a form that is toxic to fish and is generally found in higher concentrations when the pH of the water is basic, which translates into higher than 7 on the pH scale.

Adding chemical pH adjusters that are available on the market is probably the most efficient way to reduce tank pH and to keep lower pH levels you want to make sure you use real gravel for the aquarium substrate, but not crushed coral powder or sand, because they can generate calcium, which makes the pH level go up high.

8. Increase water aeration

In its toxic form, ammonia is a dissolved gas that permeates water. By increasing the aeration of the water, you can help ammonia gas diffuse out of the water and into the air. In large tanks, the aeration won’t do much to permanently fix the high levels, but it can help control them.

For this, it is advisable to use an aeration pump, which is easily found in specialized pet stores, and if the tank is covered, it should be left uncovered to ease aeration. Another way is by adding aquatic plants, which can help to produce more Oxygen while absorbing C02 and ammonia, which is great for the stress levels of fish in the tank.

9. Regular maintenance

It sounds obvious, but as mentioned before, one of the main reasons that generate ammonia peaks is the decomposition of organic matter. In the hustle and bustle of everyday life, it is easy to find that too much time passes between aquarium cleanings.

Fish tank maintenance
Fish tank maintenance

Debris, dead plants, and dirty water accumulate, leaving a breeding ground for ammonia poisoning.

Expert Tip: Performing regular maintenance, properly cleaning the aquarium elements, and changing the water all contribute to a healthy tank.

10. Water quality

The quality of the water is also important. Although your tap water typically is examined about the chemical levels it holds to ensure it is safe to use, it’s a great preventive measure to use an ammonia test kit to assure the safety of using that water.

If for some reason you live in an area where the water itself has high levels of ammonia, clearly using it in the aquarium is not a solution, and you should look for pure and balanced water.

If you must have to use tap water, let it sit for at least 24 hours, or help the process of purifying it by adding a water conditioner and ammonia remover before adding the water into the tank.

11. Use neutralizing drops

A way of fixing the ammonia levels in the tank is by using neutralizing drops. This is a temporary fix, you will still need biological filtration from healthy bacteria to break down ammonia into nitrite and nitrate, as the drops won’t eliminate ammonia but will deactivate the toxic effects of ammonia, making its toxic effects non-existent.

How do you lower ammonia levels naturally?

The answer is actually quite simple for those who are interested. The open-air tanks will release a small amount of ammonia into the air. That cleanses the water and allows the fish to breathe easily. The fish can swim and enjoy the clean water with a release function.

Some tanks are actually designed with holes to allow the water to vaporize. How do you lower ammonia levels naturally? Find a way before the fish are exposed to high levels of gas. That is known to harm the fish who are stuck in the water tank too.

Then be sure to change out the water from time to time. The water can accumulate high levels of ammonia gas. The ammonia gas is going to be worth it for all the right reasons. Take proactive steps to protect those fish too.


It is important to remember that ammonia, even in the minimum of quantities, can end up making your fish sick and stressed and if the levels increase, killing them very quickly.

Prevention is very important, that’s why understanding the common signs of high levels of ammonia in the tank, will help to identify the possible reason or reasons to address it quickly to prevent the fish to get sicker or die.

When you get a new tank it is important to monitor the quality of the water and choose the filter and gravel properly to ensure a healthy ecosystem. It may be necessary to cycle the tank before introducing the fish to ensure the aquarium is safe for them.

For tanks that are already established, regular cleaning and maintenance are crucial, as filters maintenance, and constant checking of the aquarium population. Removing all organic matter, leftover food, dead plants, and algae helps prevent levels from rising.

Constant vigilance of how the fish behave is also important, if their color loses vitality, if they have no appetite, they develop diseases, or they die. Increasing the aeration of the tank, introducing plants, and keeping the tank uncovered, will also help keep the aquarium healthy, and the fish stress-free and healthy.

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About Grace Hocker

Hi, my name is Grace and I am a pet lover. Ever since 5 years old, I've owned some sort of pet from Bearded Dragons to Rabbits. I have dedicated my life to helping pets, and am here to help you get the best for your pet!