How To Manage Nitrite Level In A Fish Tank? 11 Effective Ways

How To Manage Nitrite Level In A Fish Tank? 11 Effective Ways

You should already know that dissolved nitrogenous pollutants such as ammonia, nitrites, and nitrates are harmful to the tank inhabitants’ health (aquarium fish and invertebrates).

But what you might not know is how to manage the nitrite level in your fish tank.

So, we are here today.

In this article, we will list 11 effective ways to manage nitrite levels in your aquarium.

So, let’s start.

What Are Nitrites?

Before we explain how to manage the nitrite level in your fish tank, we need to understand what nitrite is.

For sure, your tank’s inhabitants produce ammonia as a natural by-product of their metabolism.

Ammonia and nitrifying bacteria combine to form nitrites (NO2—), a type of nitrogen or nitrogenous compounds that are naturally present in aquarium water.

When an aquarium has reached a certain stage of biological maturity, Nitrosomonas spp., which is beneficial bacteria, converts the high amounts of harmful ammonia into nitrites, which are equally hazardous.

The main issue is that there isn’t enough or any established/sufficient nitrifying bacteria to break down the nitrogenous compounds.

So, we need to know how to lower nitrite levels in a fish tank by either adding more beneficial bacteria or performing water changes.

11 Effective Ways to Control Nitrite Levels in Your Tank?

1. Lower The Fish Population Density

One way to help control nitrite levels is to reduce the fish population.

This is because with more fish there will be more ammonia produced, and this will lead to an increase in nitrite levels.

2. Add A Chemical Filter Media

If you have a filter in your tank, you can add chemical filter media to help remove nitrite.

One example of this is zeolite, which is a volcanic mineral that helps remove toxins from the water.

3. Perform Regular Water Changes

The third way to control nitrite levels is by performing regular water changes.

This will help remove the nitrite and other harmful pollutants from the tank.

4. Add More Beneficial Bacteria

Adding more beneficial bacteria will help to establish a population of nitrifying bacteria that will break down the nitrogenous compounds in the tank.

5. Add Additional Plants to The Aquarium

Adding additional plants to the aquarium will help to consume ammonia and nitrite, which will in turn help to reduce the levels of these pollutants.

They also provide a natural place for nitrifying bacteria to live and colonize.

6. Use A Bacterial Supplement Manufactured for Commercial Usage

You can also use a bacterial supplement because it will boost the number of helpful bacteria required to break down ammonia and nitrite.

One example of this is Seachem’s Stability, which is a liquid concentrate that helps to quickly establish and maintain a healthy biofilter.

7. Reduce The Amount of Food You Feed Your Fish

When you reduce the amount of food entering your aquarium, it also helps to decrease nitrification.

This will help to minimize waste generation and lessen the workload on the nitrification process.

8. Install An Aquarium Water Clarifier

An aquarium water clarifier is a product that helps to clear up the water by clumping together suspended particles and debris.

This will help to improve the overall water quality in your tank, including reducing nitrite levels.

9. Use A Water Conditioner

A water conditioner is a product that helps to detoxify the water and remove harmful pollutants.

It also helps to neutralize chlorine, chloramines, and heavy metals.

This will help to reduce the levels of nitrite in your tank.

10. Use A UV Sterilizer

A UV sterilizer is a device that emits ultraviolet light to kill bacteria and other microorganisms in the water.

This will help to control the levels of nitrite in your tank.

11. Use A Protein Skimmer

The addition of this substance will aid in the removal of organic matter and dissolved proteins from the water column before they can break down and create ammonia and nitrite.

So, a protein skimmer not only removes harmful pollutants but also helps to prevent their formation in the first place.

What Nitrite Levels Are Acceptable in Your Aquarium?

Nitrites are not good news. For this reason, the level should be 0 ppm (parts per million).

If your nitrite levels are greater than zero, you must find the cause of the problem as soon as possible.

However, there is a significant exception to this guideline… When cycling a new tank.

In a new aquarium, bacteria are not present in sufficient quantities to break down the nitrites that are produced.

This is why you need to cycle your aquarium, for the bacteria that exist in your biological filter to grow and break down nitrites.

What Happens If Your Aquarium Nitrite Levels Are Too High?

If your aquarium’s nitrite levels are too high, the health of your fish can be seriously compromised.

Nitrites interfere with the ability of red blood cells to carry oxygen.

This can lead to serious health problems for your fish, including:

1. Methemoglobinemia 

This is a condition in which too much methemoglobin is present in the blood.

Methemoglobin cannot bind oxygen, which can lead to tissue hypoxia and death.

2. Gill Deterioration

The gills are the organs used by fish to extract oxygen from the water.

If the nitrite levels are too high, the gills can become inflamed and damaged.

This will make it more difficult for the fish to breathe, and can ultimately lead to death.

3. Internal Bleeding

Nitrite poisoning can also cause the fish to bleed internally.

This bleeding can occur in any organ but is most commonly seen in the liver.

4. Lethargy

Nitrite poisoning can also cause the fish to become lethargic and not eat.

Fish that are exposed to high levels of nitrites may show signs of lethargy, including swimming at the surface or hanging out near the filter.

Also, this can lead to weight loss and generally poor health.

5. Death

Ultimately, if left untreated, high levels of nitrites can eventually lead to the death of your fish.


If you see any of these symptoms in your fish, it’s important to take action and get your aquarium’s nitrite levels back down to zero as soon as possible.

In severe cases, you may need to hospitalize your fish and administer medications to help get the levels back down.

What Causes High Nitrite Levels in Aquariums?

There are several things that can cause high levels of nitrite in your aquarium

1. New Tank Cycling

If you’re cycling a new tank, you can expect to see high levels of nitrites as the bacteria population grows and matures.

2. Overfeeding

When you overfeed your fish, you’re essentially throwing food in the water that the bacteria in your biological filter can’t break down.

This can lead to an increase in nitrite levels.

3. Poor Water Quality

If your aquarium’s water quality is poor, that means there is a high concentration of pollutants in the water.

This can include food particles, decaying organic matter, and ammonia.

All of these things can contribute to an increase in nitrite levels.

4. Improper Maintenance

If you’re not taking proper care of your aquarium, it can lead to an increase in nitrite levels.

This includes not doing regular water changes, not cleaning the filter, and not vacuuming the gravel.

Three Effective Ways to Test for Nitrites?

There are several ways to test for nitrites in your aquarium.

In this section, we’ll discuss four of the most common methods.

1. Test Kits

When it comes to measuring your nitrite levels, an aquarium test kit is the easiest and most cost-effective method.

This is the nitrite test kit that most fish stores keep on hand so it can be found almost everywhere.

How to use it?

To use a test kit, you’ll need to collect a water sample from your aquarium.

Then, you’ll need to add a few drops of the test kit’s indicator solution to the water sample.

Next, you’ll need to shake the tube vigorously and wait for the color to develop.

After that, you’ll need to match the color of the solution with the provided chart to get a reading.

Here are our recommendations:

API Nitrite Test Kit

The API test kit is a bit more expensive, but it offers superior performance.

It also includes a dropper bottle for more accurate measurements.

Salifert Nitrite NO3 Test Kit

The Salifert nitrite test kit is widely used by saltwater tank owners.

Because it costs a little less than the API kit, a lot of people prefer it.

2. Test Strips

If you’re looking for a more affordable option, test strips may be the way to go.

How to use it?

Test strips work just like test kits, but they require less precision and are easier to use.

You simply dip the strip in the water sample and wait for the color to develop.

After that, you’ll need to match the color of the strip with the provided chart to get a reading.

Here is our recommendation:

Tetra Nitrite Test Strips

If you’re looking for a quick and easy way to test for nitrites in your aquarium, Tetra’s Nitrite Test Strips may be the right option for you.

The strips are easy to use and can provide results in just seconds.

They’re also very affordable, making them a great option for those on a budget.

3. Digital Meters

If you want a more accurate reading of your nitrite levels, a digital meter may be the right choice for you.

How to use it?

You’ll need to collect a water sample and add it to the meter’s testing chamber.

After that, you’ll need to wait for the reading to appear on the screen.

Last Words

If you’re seeing high levels of nitrite in your aquarium, don’t panic, with a little detective work, you can usually track down the source and take corrective action.

Remember, high nitrite levels can be deadly to your fish, so it’s important to get them back down to zero as quickly as possible.

If you have any questions about high nitrite levels in aquariums, don’t hesitate to ask in the comments section below.