How Do I Get Rid Of Black Beard Algae In My Fish Tank? {Treat & Prevent}

Have you decided that it’s time, once and for all, to get rid of Black Beard Algae from your tank? Will many of the removal techniques end up harming your aquatic animals and plants? Take a deep breath.

In this article, we’ll dive deeper into treating and preventing Black Beard Algae in order to eliminate it from your tank.

How Do I Get Rid Of Black Beard Algae In My Fish Tank? If you can remove the decorations or plants with Black Beard Algae (BBA) growth, soak them in Hydrogen Peroxide for 3-5 minutes, rinse with water and dry before placing them back in. CO2 injections, liquid carbon, adding in Black Beard Algae eaters, reducing phosphate levels and shutting off tank lights will also help to get rid of BBA. 

What Causes Black Beard Algae?

Black Beard Algae (BBA) is also referred to as brush algae that produces clingy, fuzzy and dark hairs that attach tightly onto surfaces and plants. It can be caused by many conditions including the following:

  • Low or fluctuating Carbon Dioxide (CO2) levels
  • Too Much Light
  • Excess phosphates from decaying plant matter and leftovers
  • Inadequate water circulation

Low CO2 Levels

The low amounts of constant fluctuations of CO2 makes it hard for your plants in the tank to utilize the light through photosynthesis. At the same time, it opens the door for Black Beard Algae growth.

Too Much Light

While your plants and aquatic life require light, algae thrives on the overuse of lights. If you are routinely going over 12 hours of light in the tank per day, you are making it easier for Black Beard Algae to grow on decorations or plants in the tank.

Excess Phosphates

Phosphates tend to rise as waste is broken down in the tank. The following sources of phosphates must be taken into account:

  • leftover food
  • fish waste
  • pH & kH buffers
  • dead plant matter

Please clean your tank more often with water changes, scrubbing surfaces, substrate vacuuming, proper filtration and avoid overfeeding your fish.

Inadequate Water Circulation

Water can be circulated to increase oxygen and CO2 through weekly water changes, air pumps, powerheads, air stones or filters. Continue to allow water to pump or flow freely to reduce the likelihood of Black Beard Algae growth.


*Note: Please keep in mind that it may not have been your fault. Don’t be hard on yourself. In many cases BBA arrives to your tank without your knowledge on plants, aquatic life or decorations that may have contained BBA spores on them.

Will Black Beard Algae Go Away On Its Own?

Unfortunately, it is very difficult for Black Beard Algae (BBA) to go away without your effort. You may employ some Black Beard Algae eaters such as Siamese Algae Eaters, Florida Flag Fish, Nerite Snails and Amano Shrimp, but the algae may return.

BBA thrives on light. You may have to reduce or completely shut off all tank lights if you want it to go away on its own. A lack of light may cause harm or stress for your aquatic life and plants as well.

Thankfully, there are treatment options to help you get rid of Black Beard Algae, but they require patience, care and effort on your part along with a few purchases from your local fish shop.

How To Get Rid Of Black Beard Algae In My Fish Tank

You have arrived at this article because you are interested in finding out how to remove Black Beard Algae (BBA) from your tank. First of all, we should point out what isn’t going to work:

  • scrubbing
  • cutting
  • letting your algae eaters go to work

This type of brush algae is coarse, clingy and difficult to pull, cut or scrub off. Many algae eaters will also give up and move onto easier green or hair algae to consume because of this.

You will have to soften Black Beard Algae with liquid carbon or CO2 injections to remove it manually. At this point, your algae eating aquatic life will also have an easier time munching off pieces to get rid of it.

Method #1: Hydrogen Peroxide

You can purchase Hydrogen Peroxide from many retailers including fish shops to eradicate Black Beard Algae (BBA). There are a few ways to use Hydrogen Peroxide treatment including:

  • Remove, dip and soak affected decorations and plants.
  • Brush your affected areas inside the tank.
  • Inject it with a syringe into spaces where there is BBA growth.

Remove, Dip & Soak

If you can safely lift out any objects or plants in the tank with BBA growth on them, then do so now.

  1. Set up a bath of 3% Hydrogen Peroxide and dip them in to fully soak for 3-5 minutes.
  2. Use freshwater to rinse it all off and let them dry to make sure the Hydrogen Peroxide is removed.
  3. Finally, place them all back into the tank.

Use A Paintbrush

Please keep in mind that some plants and aquatic life are sensitive to Hydrogen Peroxide in the tank. It may also throw off your nitrogen cycle by killing some beneficial bacteria.

Gently stroke a brush with minimal amounts of Hydrogen Peroxide on affected regions of the tank where you see the slightest growth of Black Beard Algae. If the growth of BBA is too large, please try to cut it down first and resume brushing once it’s more manageable.

Inject With A Syringe

Fill a syringe with 3% Hydrogen Peroxide and begin injecting directly into the spores of Black Beard Algae that are growing on rocks, plants or other decorations.

Some plants and aquatic life will be harmed with excessive injections. It’s always best to remove your fish and invertebrates before adding chemicals like Hydrogen Peroxide or liquid carbon to remove BBA.

YouTube video

Method #2: CO2 Injections

You should be able to find CO2 cylinders in your local fish shop or online. Increasing Carbon Dioxide in the tank will weaken, soften and eventually kill off Black Beard Algae. Two effects may result:

  • Your plants will thrive off the added CO2.
  • Your aquatic life may suffer from a lack of oxygen.

Thriving Plants

The added CO2 will promote your plants to grow faster and stronger. They will absorb the nutrients available in the tank and reduce the chances of the algae from flourishing. This is a gradual process and may take several injections to complete the job.

Lack of Oxygen

You may notice your fish gulping for air, glass surfing and getting stressed from a lack of oxygen. This is why it is important to be gradual, patient and inject CO2 in small amounts over a longer course of time.

The best recommendation is to remove your aquatic life, if possible, into a quarantine tank until you can get a stranglehold on your Black Beard Algae problem.

Method #3: Liquid Carbon

Liquid carbon is produced and sold in many fish stores under names like, Flourish Excel, Easy Carbo with a chemical called, Glutaraldehyde which helps Black Beard Algae wither away and gradually die off.

You can dose the areas affected with a syringe or pour small amounts as directed on the bottle into the entire tank. Continue to check pH levels and use water changes to prevent your aquatic life from suffocating from a lack of oxygen.

It’s also best to dose at night when the lights are off to remove any nutrient absorption for the BBA to start turning purple or reddish brown. Once it loses color, turns pale, then you can say goodbye to BBA or brush algae.

Side effects include:

  • Plants may also wither or melt away. 
  • Fish and invertebrates may gasp for air. 
  • Nitrogen cycle or beneficial bacteria may break or die. 

Method #4: Tetra Algizit Tablets

This product boasts its ability to eradicate many types of algae from your tank. Follow the required dosage carefully on the packaging. It arrives in tablet form and is usually meant to be used as follows:

  • 1 tablet per 5 gallons of water
  • dosage must not exceed 4 weeks

Your plants, fish, invertebrates and beneficial bacteria are meant to be safe with this procedure. Since BBA is one of the toughest forms of algae out there, this method may take up to 4 weeks with varied levels of success.

Method #5: Lights Off

Black Beard Algae requires light to survive. Kill off the lights to kill the intruder. Many plants may go through a difficult time if they are not hardy enough to make it through the blackout.

Start with 3 days without light and gradually add 4-5 hours of light on the fourth day and so on. Make sure there is plenty of water agitation by using an air pump if you wish to keep your aquatic life in the tank during this time.

The BBA should be weakened to the point where you can remove it manually at this point in time.

Method #6: Reduce Phosphates

Phosphates rise when there is too much waste or debris in the tank. An improperly maintained or neglected tank will have too much decaying plant matter, fish waste or leftover food.

  • Scrape and scrub the tank first.
  • Vacuum the substrate.
  • Do not overfeed your aquatic life.
  • Use filtration where the filter’s media is capable of absorbing phosphate.

Method #7: Boil It

If you have decorations and rocks with Black Beard Algae (BBA) growth, remove them and try a chemical free approach. This will obviously not work with live plants.

Place the décor in a pot of boiling water. It will only take a few minutes or so to kill off BBA.

Method #8: Algae Eaters

Please check out our extensive article: What Eats Black Beard Algae? In it, we go through great details on all the aquatic life that you can employ to help take care of your Black Beard Algae problem.

We would like to mention our top 6 favorite fish, top 3 shrimp and top 3 snails below who are known to nibble or munch on BBA.

Top 6 BBA Eating Fish

  1. Florida Flag Fish 
  2. Chinese Algae Eater
  3. Flying Fox
  4. Rubber Lip Plecostomus
  5. Twig Catfish
  6. Siamese Algae Eater

Top 3 BBA Eating Shrimp

  1. Cherry Shrimp
  2. Amano Shrimp
  3. Cardinal Shrimp

Top 3 BBA Eating Snails

Please keep in mind that most of these algae eaters would prefer it if you soften or trim the BBA first. You can do so by adding CO2 injections and using trimmers if the BBA has overgrown and established itself in your tank for too long.

What Kills Black Beard Algae Naturally?

The natural born killers of Black Beard Algae range from a series of aquatic life to using heat or a lack of light. When using heat, you will have to remove any decorations and boil them. Do not increase the temperature in the tank.

The following list of live Black Beard Algae eaters are presented below:

  • Florida Flag Fish
  • Golden Algae Eaters
  • Chinese Algae Eaters
  • Flying Foxes
  • Bristlenose Plecos
  • Rubber Lipped Pleco
  • Siamese Algae Eaters
  • Black Molly 
  • Twig Catfish
  • Otocinclus Catfish
  • Rosy Barb
  • Cherry Barb
  • Nerite Snail 
  • Mystery Snail
  • Malaysian Trumpet Snail
  • Cherry Shrimp
  • Amano Shrimp
  • Cardinal Shrimp

How To Stop Black Algae Spreading?

Stopping the spread of BBA involves your immediate response to catch it as early as possible. You can dim the lights more often to reduce the amount of nutrients it can receive.

You should also make sure there is enough Carbon Dioxide in the tank for your plants to thrive while the algae loses its ability to take over. Your algae eating aquatic life will also help you to prevent the Black Beard Algae from spreading.

The first step is to always remove any decoration or plant that is affected. If the plant is firmly rooted, you can try injections of CO2 and careful applications of liquid carbon or Hydrogen Peroxide.

How To Prevent Black Beard Algae

The following tips are here to help you with any future breakouts of Black Beard Algae:

  1. Make sure you are buying plants, aquatic life and decorations from reputable shops to limit the transfer of algae spores.
  2. Quarantine plants, decorations and aquatic life in their own ways. Research further into quarantine methods such as using sunlight, heat, Hydrogen Peroxide and quarantine tanks.
  3. Reduce your lighting and never go over 12 hours of lights on per day.
  4. Always change the water 10-25% per week or two depending on your tank conditions.
  5. Vacuum the substrate once a week.
  6. Add more live plants to take the nutrients away from algae.
  7. Remove leftovers and do not overfeed your fish.
  8. Make sure your filter is an appropriate size for your tank.

We hope you have been able to get a handle on future algae growth and we wish you the very best of luck.

Frequently Asked Questions

Is Black Beard Algae Harmful To Fish?

Black Beard Algae (BBA) is not harmful. Many aquarists find ways to trim down the BBA overgrowth on decorations to create a manageable space for it to grow tightly and possibly even making it look attractive with its hairy appearance. BBA will take nutrients away from plants if they grow on their leaves. Your aquatic life will not mind BBA.

Will Goldfish Eat Black Beard Algae?

No. Although goldfish do enjoy nibbling on various types of green algae, Black Beard Algae is simply too coarse and tough to pull, bite and nibble on. You will not be able to control your Black Beard Algae problem with goldfish. Try a Siamese Algae Eater instead.

What Does Black Beard Algae Look Like?

Black Beard Algae looks hairy as its name suggests. It can take on dark green, gray or blueish tints. They belong to the red algae group, but they are not red in appearance. Black beard Algae is tough to remove as it grips onto surfaces when there isn’t enough CO2 in the tank.

Do Snails Eat Black Beard Algae?

Not all snails will be able to eat the thick and stubborn hairs of Black Beard Algae. We have seen relative success with Nerite Snails, Mystery Snails and Malaysian Trumpet Snails. Do not expect your Black Beard Algae problem to be eliminated with snails alone.


We hope that with the methods provided today, you will be able to take back control of your tank and get rid of Black Beard Algae once and for all. Remember that you do not need to apply every method.

Seek out your best option after careful consideration and always look for the help of a few Black Beard Algae eaters. For a comprehensive list of What Eats Black Beard Algae, please check out our next article that concentrates solely on these helpers.


Thanks for visiting with your concerns or curiosity surrounding Black Beard Algae. We have plenty more informative articles on algae and other aquatic life that may also be of interest to you. See you soon!

Brian Arial

Brian Arial has kept fish for leisure and worked with fish stores for most of his life. He enjoys writing and caring for aquariums and ponds.

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