How Do You Get Rid Of Bacterial Blooms In An Aquarium

Do you notice the emergence of an unwanted cloud in your fish tank? Are you having a hard time getting rid of them? Do you need an easy and effective solution to this problem? If your answer to any of these questions is yes, this piece contains the most valuable information for you.

To get rid of bacteria bloom, remove all dead and decaying matters in the tank. Carry out partial water change and ensure that your filters and other tank equipment are functional. Using clearing enzymes and reducing fish foods work well too.

What Is Bacteria Bloom?

Bacteria bloom is also known as bacteria blossom. It is a condition in the aquarium when there is a sudden spike in the number of bacteria colonies. These microorganisms are apparent to the point of clouding the tank’s water.

The bacteria colonies become suspended on the water surface. You might not see any floating particles, but the water becomes less transparent. Bacterial blooms in fish tanks are undesirable. Besides the fact that it makes your fish tank unattractive, it endangers the lives of your fish.

What Causes Bacterial Bloom?

Bacteria bloom can occur in a fish tank due to several reasons, and one of the primary causes of bacteria blooms is the rise in organic matter. This matter favors the growth of bacteria; hence, it leads to a bacteria bloom.

Organic matter can get into the tank via various means. One of the most common ways is through fish foods. It occurs when you overfeed the fish. The food leftovers can decay in the fish tank, thereby favoring bacteria growth.

Another cause of bacteria bloom is dead or decayed plants and fish. Live plants are suitable in fish tanks only when they are alive and growing. It facilitates bacteria bloom when it becomes dead and starts decaying.

The same rule applies to dead fish. Regardless of the cause of the fish’s death, it starts to favor bacteria bloom once it starts to decay.

Once the heterotrophic organisms in the fish tank find these organic matters, they multiply rapidly. This process causes a spike in the number of bacteria colonies. Their increased number makes it easy to attach to the water surface; hence, bacteria bloom.

Other notable causes of bacteria bloom include;

  • Using untreated water for your aquarium, especially tap water that contains chlorine. Chlorine can kill good bacteria and favor bacteria bloom.
  • Cleaning your aquarium materials like filters with untreated tap water or chlorinated water.
  • Cleaning or changing both gravel bed and filter media simultaneously.
  • Accidentally introducing various organic pollutants to the tank. These pollutants can include untreated substrates.
  • Overcrowding the tank with fish, plants, or substrates. It will cause a significant natural imbalance that will favor bacteria bloom.
  • Dysfunction of various aquarium equipment, including filters and pump.
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What Does Bacterial Bloom Look Like?

Identifying bacteria bloom in a fish tank is not rocket science. It becomes apparent when the bacterial colonies fully attach themselves to the water surface. The first noticeable appearance is the reduction in water clarity.

The signs become more apparent in a few days. The water turns milky and becomes cloudy. In extreme or severe cases, it becomes difficult to see your fish and other tank materials.

However, floating particles will not be visible to naked eyes. Also, you won’t be able to identify distinct colonies until you view them under a microscope.

Is A Bacterial Bloom Good or Bad for Your Aquarium?

Although there are some healthy bacteria, bacteria bloom is in no way beneficial for your tank. The bacteria bloom might not harm the fish directly but becomes dangerous in the long run. It can cause reduced oxygen levels in a fish tank.

Reduced oxygen levels will stress out your fish. You will find them gasping for breath at the surface of the tank. If the condition persists, it might lead to the death of the tank inhabitants.

Besides, bacteria bloom makes your tank vulnerable to parasite attacks and infection. First off, stressed fish are prone to these attacks. Also, the cloudiness will prevent you from seeing your fish in case of any symptoms.

Aside from these, bacteria bloom will take away the beauty of your aquarium. It will cover the beautiful colors of your fish and the lovely plant additions.

How Do I Get Rid of a Bacterial Bloom in My Aquarium?

Getting rid of bacteria bloom should be the prompt line of action once you discover this problem. Start by figuring out the cause of the bacteria bloom. Identifying the cause can be an excellent pointer to the possible solution.

Start by getting rid of the cause of the bloom. Evacuate dead fish or plants from the fish tank. Other methods include;

1. Use Suitable Clearing Enzymes

You can also address this condition by using enzymes. These enzymes perform quick clear-ups, and they are available for sale in most pet stores. All it requires is using the package as prescribed by the manufacturer.

2. Fix the Aquarium Filters

Alternative treatment includes inspecting and fixing the aquarium filter. Figure out and fix the filter if it is either blocked, broken, or dirty. Repairing or replacing filters can get rid of bacteria bloom overnight.

3. Perform Water Change

Performing regular water change is a standard way of maintaining the tank’s cleanliness. This option is also valid for tacking bacteria bloom. All you need is a 20% water change. But you can consider increasing it to 30% if the bacteria bloom is severe.

Avoid making 100% water change. Complete water change can destabilize your fish and cause stress. The healthy ones might acclimatize with time, but some might not survive it.

4. Reduce Your Fish Foods

It is OK if you want your fish to get enough food for their growth. But it is not OK to overfeed them. Feed with only food quantities that you are sure they can finish.

In case there are leftovers, ensure that you get rid of them immediately. But reducing the fish food is the best bet.

Can I Add Fish During Bacterial Bloom?

Adding fish to your tank during bacteria bloom might not be as dangerous as it seems. You can continue introducing new fish to the tank as long as the nitrate and phosphate levels are zero.

The only hassle is ensuring the zero level of phosphates and nitrates. It is also crucial to ensure that other water parameters are suitable for your new fish.

Similarly, it is best to avoid adding too much fish during this period. Overcrowding the tank during bacteria bloom can worsen the case. It raises the risk level and makes the solution extra tedious.

Why Is My Tank Still Cloudy?

In some cases, a cloudy tank as a result of bacteria bloom will clear on its own. But you might need to take action if you want to remove it faster. However, there are some cases where the tank remains cloudy, even after treatments.

Cloudy fish tanks typically clear after ten days. It will take fewer days if you apply appropriate treatment and preventive measures. So, you might have to be patient! All you need to ensure is that you already get rid of the cause.

If the cloudy tank persists after ten days, consider intensifying the treatment techniques above. Also, you can consult aquarium treatment specialists on the subsequent line of action. But excessive persistence of cloudy tanks is rare.

How to Prevent Bacteria Bloom?

Prevention is better than cure! This rule still holds for bacteria bloom in a fish tank. There are standard and straightforward ways to prevent bacteria blooms in your fish tanks.

Some of these preventive measures include;

  • Make sure that the aquarium filter and other equipment are clean and in perfect working condition.
  • Perform regular water changes and ensure proper cleanliness of the fish tank.
  • Maintain good hygiene and avoid overcrowding in the fish tank.
  • Dose your aquarium with beneficial bacteria or suitable enzyme once in a while during cleaning.
  • Monitor nitrate and phosphate levels in a fish tank and keep them at zero level
  • Avoid overfeeding your fish and get rid of leftovers immediately.
  • Evacuate dead fish or plants from the aquarium as soon as you discover them.
  • Regular tank and water inspection will help the overall quality of your tank.

You might notice that the preventive measures are simple maintenance culture. They are also similar to the cures. But it is best to carry them out before bacteria bloom occurs; that’s what makes it prevention.


Bacteria bloom is a common occurrence in aquariums, particularly new tanks. It results from a spike in the number of bacteria colonies in the tank. The colonies attach to the surface of the tank and cause them to become cloudy and milky.

Bacteria bloom might not be directly harmful to your fish. But they facilitate some risk factors that endanger your fish’s life. So, it is best to prevent and get rid of bacteria bloom in your aquarium.

Preventing and eliminating bacteria bloom from the fish tank is not rocket science. It involves basic cleaning and maintenance cultures of your aquarium. Feel free to try various solutions till you get one that works for you!