Four Unusual Places Where Beneficial Bacteria Live In Your Aquarium

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Many aquarists debate the fact that beneficial bacteria are essential for the tank. This can be true to some extent. However, you might also be growing some bad bacteria that may harm the health of your fish. So, where do these beneficial bacteria come from or live in your aquarium?

Well, the beneficial bacteria reside anywhere in the tank where the debris and dirt can accumulate. This can mean that the beneficial bacteria are in your decorations, substrates, plants, as well as other equipment in your tank.

Let us know more about beneficial bacteria in detail so that you do not make any rookie mistakes.

What Does Beneficial Bacteria Mean In The Fishkeeping World?

Beneficial bacteria are the tiniest single-cell microorganisms that reside in your aquarium and play an important role in the nitrogen cycle. The bacteria are formed by the nitrogen cycle of your tank.

They can be both bad and good bacteria in your aquarium. The bad ones will cause diseases and spoilage of food while good bacteria improve and support the growth of your tank buddies.

The beneficial bacteria have many more advantages that I will discuss in the sections below.

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How Are Beneficial Bacteria Formed In An Aquarium?

The forming process of the beneficial bacteria gives us the idea of where it sits in the aquarium.

Let us learn about how they are formed first. Every aquarium is unique! So, maybe yours has a different place where the bacteria grows. Beneficial Bacteria is formed by the following process:

  • Basically, any living being residing in your tank will help to grow the beneficial bacteria in your aquarium. These living beings can be your fish, plants, etc in your aquarium.
  • If you have filtration running in your aquarium, fish poop, excess foods that go uneaten by the fish, and various branches as well as leaves of plants fall and sit on the bottom of the tank. They may also attach to the substrates.
  • Now, this is when the deadly ammonia appears in your tank water. You have to clean your aquarium often to avoid ammonia poisoning.
  • Similarly, when the ammonia is formed in your aquarium, bacteria starts to grow. This is a natural process to convert ammonia into nitrite through these bacteria.
  • In the next step, nitrite will push the growth of bacteria furthermore. Now the bacteria will convert nitrites into nitrates to decrease toxicity in the tank water.

Note: Although nitrate is not much harmful to your fish and other living beings in your tank, you should still keep them in control. To keep the nitrate, nitrite, and ammonia in control, you can change the water of your tank frequently. To know more about “Is Too Much Water Change Harmful For Your Fish and How To Do It Safely”, click here.

Does Beneficial Bacteria Live In The Tank Water?

Many people confuse themselves about having beneficial bacteria in the tank water. But this is a false concept.

Beneficial bacteria do not live in the tank water but they reside in the pieces of equipment that you have in a tank. It may be the decorations, walls of the aquarium, plants, and many more.

Where Does Beneficial Bacteria Live In Your Aquarium?

Bacteria attach themselves to some living beings or the decorations in your tank. It is not a part of your tank water. The bacteria sticks itself to various pieces of equipment in your tank like substrates, walls of your aquarium, plants, decorations, etc.

You can also check our article on How To Setup A 20-Gallon Fish Tank: Livestock and Equipment List.

Filtration System

Not only this, but you can also expect to find these beneficial bacterias in the filtration system of your tank. This is generally seen in biofilters as well as sponge filters.

Moreover, the beneficial bacteria can attach themselves to the inside of the filtration system and live there for quite a long time if you do not clean them often.

Additionally, I will give you a tip. Rinse the filter media whenever you keep it in. Similarly, tap water is a great way to wash the bacteria off of your tank. However, Tap Water can be unsafe for your fish. So, find out How to Make Tap Water Safe?

Using the tank water to rinse away the filter media will only cause trouble because the bacteria will still be healthy and living. This is not something you would want in the tank.


Substrates are the gravel, sands, etc that you use in the bottom of your tank. They are quite stern but the beneficial bacteria will find a place to reside in them.

Especially when the remaining food and fish poop get stuck in the bottom of your tank, the beneficial bacteria start to form. So, you have to clean your tank. I have mentioned the easiest way to clean the tank that you may not have found elsewhere in my other article.

To remove the bacteria from the tank from your substrate, all you need to do is clean the tank by scrubbing the inside glass. You can also try siphoning up the substrate.

However, there might be a certain increment in ammonia and nitrite. So, change your water frequently to avoid such spikes.


When the plants are leafy, they attract dirt, debris, and excess food to their body. It is especially the case with mosses like the Java Moss. The way to clean the plants is just to remove them from the tank water, rinse them with tap water, and put them back.

You can learn to set up a nano planted aquarium from our Set up Guide. Besides, you may also check Fish to Avoid For A Planted Aquarium.

In contrast, if you have a rooted plant, you will have to change the water and clean the tank frequently.

Decorations And Ornaments

Basically, bacteria sit everywhere the dirt, debris is attached to. It is the same with decorations and ornaments too. If your decorations and ornaments have a lot of space in them which can collect the plant debris and excess food, then the bacteria is on its way to formation.

The way to clean the decoration and ornament is the same as plants. They will be easier to clean if there are less artwork and fewer places you can’t reach.

If you are a beginner in the fishkeeping world, learn about Aquarium Decorations: What To and What Not To Add from our Beginners Guide.

Benefits Of Beneficial Bacteria In Your Aquarium

There are various benefits of beneficial bacteria in your aquarium. They are:

  • Beneficial bacteria help to keep the nitrogen cycle running.
  • Similarly, they also keep the aquarium water lively.
  • A natural way of cleaning the tank and removing detritus.
  • Maintains a healthy environment for the fish in the tank.

You might be interested in articles like How To Get Rid Of Algae In Fish Tank Naturally and Benefits of Keeping Fish | Health Benefits, Vastu Shastra.

How Long Does It Take For Bacteria To Grow In Your Aquarium?

If you are looking for growing bacteria in your tank, then you must be trying out various ways to do so. Every method gives you different results. So, it might take a different amount of time.

Among the various methods, using the filter media or substrate is the fastest way to grow beneficial bacteria in your tank. This method will require you only two weeks.

Similarly, for setting up a new tank, you must let at least four to six weeks to do the job. If you do not have much patience, add some of the fish food flakes to the tank. The bacteria will grow in some weeks to decompose the ammonia into nitrite and nitrate respectively.

You can also learn more about How To Set A 50-Gallon Fish Tank.

How To Make The Aquarium Free From Bacteria?

Beneficial bacteria in the aquarium can help you in many ways. But some people might not like the idea of bacteria residing in their aquarium.

Especially when bad bacteria start growing in your aquarium, it can cause many problems. Since it can cause your tank water to get cloudy or yellow in some cases, it makes sense to remove bacteria from the aquarium.

To make the aquarium free from bacteria, you can do the following things:

Other Steps To Follow For A Healthy Tank

There are some other things that you have to do to follow up the cleaning process to keep the tank fresh and healthy.

Frequently Asked Questions

How To Get Beneficial Bacteria In The Aquarium?

Do you want beneficial bacteria to live in your aquarium? You can use the natural ways that I have mentioned before like setting up a new tank and putting in some fish flakes.

Similarly, you can also add up some bottled bacteria and put it in your tank.  However, I would say that you do not have to use bottled bacteria. And even if you do use it, make sure that you are experienced in that area.

You can also try to add more fish to the tank. This will surely ensure more excess food and poop. The bacteria will grow in no time at all.

Not only this, you can also use bio filters or sponge filters in your aquarium to bloom the growth of bacteria in your tank.

Can You Add Too Much Bacteria To A Fish Tank?

Adding a commercially bottled bacteria, it would not be much of a good option. Adding too much bacteria would only create problems in your tank as the bacteria might bloom. Besides, they would also die out and your money would go to waste.

Although, if you have plants in your aquarium, you may use one. API QUICK START Freshwater and Saltwater Aquarium Nitrifying Bacteria 16-Ounce Bottle gets the results faster. I would suggest you to use it in tank water but do not add fish in them for 3 to 7 days as there may be a change in the water parameters.

How Long Does It Take For Bacterial Bloom To Go Away?

If you are wondering what bacterial bloom is, it is the excessive bacteria that grows to the point where the water grows cloudy. It especially occurs during the nitrogen cycle.

The cloudy water goes away when the ammonia and nitrite will clean up. The time is from 2 to 6 weeks.

If it takes more than that, you have to clean your tank properly in parts. Ammonia and nitrite level strike high if you do it all at once.

Last Words

In a nutshell, the beneficial bacteria live in various equipment that you have in the aquarium where the detritus or excess food goes to stay and accumulate. The bacteria does not reside in the tank water but in the decorations, substrates, walls of your aquarium, etc.

These beneficial bacteria are very useful for your aquarium as they maintain the nitrogen cycle of tank water. Similarly, it will also help to keep the tank clean to give the perfect environment for your fish buddies.

I hope you got the idea about beneficial bacteria and where it lives in the aquarium. You can put your queries in the comment section below!

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