How to Remove Black Beard Algae from Your Aquarium?

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Black beard algae, also known as black brush algae (BBA) is a very common algae type, which is present in most of planted aquariums. It is one of the hardiest algae types out there. And it is very hard to kill, and there are very few fish, which will consume it.

It is easy to identify: it is black, reddish, grayish color and has grows in a beard or brush shape on the leaves of slow growing plants, rocks or other aquarium decoration.

If you have an Anubias plant in your fish tank, sooner or later you will most likely have black beard algae. In this article I will show the causes of black beard algae and ways to if from your anubias plants, or other slow growing plants without cutting the leaves.

But first, let’s see what is causing BBA to grow and why is so common on Anubias plants and other aquarium decorations?

How Does Black Beard Algae Get Into Aquariums?

Just like any other algae, black beard algae are reproducing through spores. These can be introduced into an aquarium via plants, fish, or fresh water. Spores can swim around for weeks or months in your aquarium, and when the conditions are right, the BBA will start growing and spreading.

And there are not many things that can stop it from overtaking whole aquascapes and aquariums.

Main Causes of Black Beard Algae

Research shows, that black beard algae is caused by excess of vitamin B12 in the water column.

From my fish-keeper experience, black beard alga is common in aquariums with strong lights. The lack of CO2 or its fluctuation can also cause the appearance of BBA.

Black beard algae is also a sign of inefficient filtration system, because BBA grows in the presents of high nitrites.

Excess nutrients in the water can also cause black beard algae.

In water, where the concentration of calcium is above average, the calcium will build into the tissue of the algae. In this case algae eating fish and shrimp will not even touch it.

Is Black Beard Algae Harmful to Your Fish or Plants?

BBA is not harmful to your fish at all. Plants, however can suffer from BBA if it is not treated in time. Black brush algae will start growing on the tip of the slow growing plant leaves and will spread overtime to the whole leave.

If neglected, BBA will take over your whole Anubias plant. It will slowly kill your plant, by blocking the lights off and making photo-sensitization impossible for the plant.

Black Beard Algae Eating Fish & Shrimp

There are not too many fish that will eat black brush algae. In fact, I only know one fish and a type of shrimp that will consume BBA.


Siamese Algae Eater Fish

The Siamese algae eater fish (scientific name: Crossocheilus oblongus) is the only freshwater aquarium fish, that will consume black beard algae. There is no guarantee though, that they will clean your tank from BBA. Just like humans with food, they also have preferences in algae types they consume. You might get a Siamese algae eater fish, which does not like the BBA. Or the BBA in your tank is so old and full of calcium, that the fish will not be able to eat.

Siamese algae eater can grow up to 6-7 inches (15-20 cm) in size. The minimum of 50 gallon (200 liters) aquarium is recommended for them. It is a social fish, so it is recommended to have at least 3 of them (6 is the best) in your tank, otherwise they can become very aggressive and territorial.

If you have a small tank, the Siamese algae eater might not be suitable for you to get rid of black beard algae.


Amano Shrimp

Amano shrimp are also great algae eaters and they also consume BBA. They will grow up to 2 inches (5 cm) in size, so it might suit a small aquarium. The problem with Amano shrimp is that they will only consume black beard algae if there is no other type of algae or food available in the tank. So this might not be a good option to get rid of BBA.

Can You Remove BBA by Hand?

As mentioned before, black beard algae is one of the toughest algae type. It sticks so strongly to plants and decoration, that with bare hands it is almost impossible to remove.

From decoration it might come off with heavy scrubbing and hot water or bleach, but from leaves it will not come off easily.

I’ve managed to remove / scrape BBA from Anubias and other slow growing plant leaves with the ADA Pro Picker, but it took me a lot of time and effort.

How to Remove Black Beard Algae from Anubias Plants?

Most people will recommend you to cut off all the leaves from your plants that are infected with black beard algae. This is probably the easiest option, but it is very brutal and will probably kill your Anubias plant.

You can add a CO2 system to your tank. With CO2 and proper nutrients, your live plants will start growing faster and will outcompete algae. BBA will start dying off and eventually will disappear totally from your tank. CO2 though is very expensive. Once you stop dosing CO2 to your tank, BBA will come back. Setting up a CO2 system is also a bit complicated.

There is an easier and cheaper way to remove BBA from Anubias plants.

Browsing the internet and some fish-keeping related forums, I came through a very good method, which I had to try out:

“Brush off the black brush algae method”

What? How to brush off the BBA from an Anubias plant? Well, the method is peaty simple. You will need Flourish Excel (buy it from Amazon) and a small brush for this.


Flourish Excel is basically liquid carbon, which is a relative good alternative to CO2 injection. It will help plans to consume nutrients from the water more efficiently.

Dosing Flourish Excel to your tank, will help get rid of most algae types, but not from BBA. To remove black beard algae from your tank with Flourish Excel, you will need to overdose. Overdosing however can harm your fish, and kill all your more sensitive plants.

I’ve managed to kill all my water wisteria from one of my fish tanks by overdosing Flourish Excel. I’ve also noticed that crypts don’t like Flourish Excel and will slowly melt away.

So what is this brush technique all about?

It is similar to the bleaching technique, but it is way simpler and the risk is much lower. Here are the steps you should follow:

  • Remove your Anubias plant from your aquarium and let it dry for 5-10 minutes
  • Apply the Flourish Excel to the affected leaves with a small brush
  • Leave the plant for 5 minutes with the solution on the leaves
  • Put it back into your aquarium and leave it alone for a few days

In just 1-2 days, you will see the black beard algae losing its color or shade. After 3-4 days BBA will become thinner and lighter in color. It will become grey in color. Fish will start nibbling on the BBA and will help cleaning it off from your plant. Eventually after 5-7 days, the BBA will be completely gone.






If the black brush algae is not completely gone in one week, repeat the process.

The good thing with this technique is that the leaves of your plant remain intact. They might get damaged a bit due to the strong compounds found in the Flourish Excel, but the loss will be minimal. The Flourish Excel will not affect your other plants, because it is only used once in a very minimal dose. Unlike bleach, in small doses Flourish Excel it is not harmful to your fish and plants.

Wrapping Up

I hope that this article has helped you remove the black beard algae from your Anubias plant, and gave you some good ideas on how to get rid of it completely from your aquarium.

The best method is still to prevent algae growth. Add fertilizer to your tank to help plants grow faster. Add fast growing plants to suck up excess nutrients from the water faster. Maintain your tank regularly and do weekly water changes.

Do not overdose Flourish Excel or other liquid carbons, because it will do more harm than benefit to your aquarium.

The key is to be patient and do not disturb your aquarium too much.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
Questions and Answers

Dear Fabian,

I have always loved fish but only recently invested in a larger tropical tank, since March. (I had a smaller, less populated tank previously) I have also for the first time had live plants together with the fish. I have noticed that I appear to have BBA growing. I am nervous about adding seachem flourish excel in case it upsets some of the fish (I have two dwarf blue rams amongst others) I’m quite interested in trying the brush technique on my anubias. I am not quite sure how I am supposed to replace them in the tank though. They have extensive roots but need to settle and grow into the bark? Once removed, How do I get them back in properly?

    I usually attach my anubias plants to rocks or drift wood, so it is much easier to remove. I use fishing line to secure the plants. Once I see BBA on their leaves, it is very easy to remove the plants from the aquarium without disturbing too much the aquarium. I recommend you do the same.

Trudie Robson September 25, 2020 Reply

I have BBA throughout my entire tank. My tank is a 29 gallon. I have a Beta, 6 Harlequin Rasboras, 8 Neons, and a few platy’s. i have live plants which are all covered with BBA. I have tried Excel by the recommended doses but it didn’t work. Can you help with a dosage that won’t kill my fish but will kill the BBA

    As I mentioned in the article, I don’t recommend overdosing Flourish Excel; this was only an experiment done by me.
    If all your plants are covered with BBA, it might be worth removing the affected leaves to remove as much algae as you can, get some fast growing plants and dose Flourish Excel as recommended.

Hi Fabian,
I was wondering if the brushing flourish method would work on ornaments too, especially fragile ones that may be hard to scrub?
Just a thought. Pity I can’t paint the inside corners of the tank with it.

    Hey Mark! Absolutely, this method will work on ornaments too, though it is much cheaper if you soak the ornaments in hot water, because black beard algae will die off this way too.

    BBA is very resistant to temperature change, even to hot water. The plants will die in hot water and probably the BBA will live.
    I’ve tried to wipe off BBA from decorations with hot water, and it was really tough.

Texas Andy Aquatics March 26, 2021 Reply

hey Fabian, so for the most part this was a very well written article. The only critiques i have is that (in my opinion) the Florida flag fish is a much better algae killer. They seem to be very interested in attacking BBA and GHA and the best part is you don’t have to completely starve them like Siamese algae eaters and Amano shrimp. Plus SAE stop eating BBA as they age while the flag fish continues on for (as far as ive seen) its whole life. Another thing with excel and any most other “liquid co2” is they claim it to be “liquid co2” but in no way shape or form is it actually liquid co2. Yes, excel does work great in killing algae, but due to the fact it consist of glutaraldehyde which is an algaecide and can be used for algae removal and to sterilize medical equipment. The stuff is nasty and can actually harm a human if you smell it or get it in your eyes or wounds. Now think if this is something that can possibly burn a human by it getting on your skin imagine a fish swimming threw it. I’ve kept planted tanks for over 15 yrs and encountered BBA on multiple occasions like anyone would being in the hobby for any considerable amount of time and what I’ve found is the best way to kill it is spot dosing with a syringe using 3% hydrogen peroxide. try not to exceed 10ml per 15 gallons. Do this daily for about 3-5 days then do a water change. Hydrogen peroxide does in fact gas off after about 24 hours but like dosing any chemicals into your tank be careful .P.S. if its possible for you to pull the plants, wood, decor, ect out of the tank and soak in hydrogen peroxide for 3-4 minutes then rinse and place back in tank or another container(with DE chlorinated water). Do this as well for about 3 days and unless there is BBA on the roots try to keep them out of the peroxide. Also if you see any signs of your critters being in stress (gasping for air, swimming erratically, trying to start shedding its shell(shrimp)) then do a 40-50% water change and know your dosing too much. Be safe, keep those tanks clean, dont be scared to try something new, and add more LIVE PLANTS to every tank. Thanks again Fabian

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