Black Beard Algae: Treatment, Removal, Cause & More


Scientific NameAudouinella
Common NameBlack Beard Algae
Growth HabitatBoth saltwater and freshwater

How to Identify Black Beard Algae

Black Beard Algae is an extremely common type of algae to find in your aquarium. Chances are, if you have algae in your tank, it is Black Beard Algae. Black Beard Algae belongs to the red algae family. It is also known as brush algae, black brush algae, or sometimes just by the initials BBA.

Black Beard Algae grows on the edges of plants, and any surface of the aquarium. It is made up of very fine strands or tufts of dense patches. It resembles a beard, which is how it earned its name. It is black in color, but it can show up as bright green, blue green, and blackish green. It starts off as a small patch of short fibers, but they will quickly grow longer if left unchecked. It can grow in both saltwater, and freshwater tanks. It will typically start off on the edges of plant leaves and it will quickly grow to cover the whole leaf.

Black Beard Algae doesn’t release toxins in the water, or steal nutrients from plants, but it can kill your aquarium plants if it completely covers them blocking out all their light. It can also lead to imbalances in your water, and make it an unsafe environment for any fish in the affected aquarium.

If you spot a small amount of Black Beard Algae in your tank setup it isn’t that big of a deal, but keep in mind that it can also take over your aquarium rapidly, and it is impossible to remove by hand. It is also very slimy and unsightly.

Black Beard Algae

What Causes Black Beard Algae Growth?

The primary cause of Black Beard Algae is contaminated plants, substrate, or decorative items that have been introduced into the aquarium. If your aquarium has inadequate water circulation, or if your CO2 levels are not at a sufficient level, or the levels fluctuate, then that’s creating an environment that’s perfect for algae growth.

It is always a good idea to monitor the balance of the tank. The carbon dioxide levels, nutrients, light, and regular water changes should all be considered when balancing your aquarium. Ensuring this will eliminate the breeding habitat for unwanted algae.

As with most aquarium dwelling things, Black Beard Algae loves the light. The more lighting you have, and the longer you leave it on for, the faster it will grow. It is recommended you cycle the light source to help prevent growth. In fact, choosing to cut back on your lighting, or even leaving it off for a few days can stop algae in its tracks, and may even kill it altogether without having to use other potentially harmful methods.

Fish that Eat Black Beard Algae

Black Beard Algae isn’t necessarily harmful to your plants and fish, it can still cause issues in your aquarium, and if left unchecked it will quickly take over. However, as much as it isn’t harmful, it is unsightly. It quickly grows to cover plants and decor. There are some fish that will eat Black Beard Algae and help keep it from taking over, but they are not an effective method to rid your aquarium of major Black Beard Algae growth. Here is a list of fish that will eat Black Beard Algae.

  • American Flagfish
  • Black Molly
  • True Siamese Algae Eater
  • Chinese Algae Eater
  • Twig catfish
  • Bristlenose pleco
  • Rubber lipped pleco
  • Pygmy suckermouth
  • Rosy Barb
  • Cherry Barb
  • Common Goldfish

Black Beard Algae Treatment and Removal

Thankfully, there are ways you can rid your aquarium of Black Beard Algae before it gets out of control and causes a nutrient imbalance, or kills your aquatic plants. As with most things, a bit of prevention is worth all the cure, and having Black Beard Algae in your aquarium is no different.

You can prevent Black Beard Algae from getting a foothold in your tank by making sure you get your fish and aquatic plants from a reputable store, quarantining new fish for at least two days before adding them into your tank, and by soaking any new plants or decor that you get in a ten percent bleach solution for a few minutes before adding them into your tank.

Still, even with all these methods of prevention, it is still possible to get Black Beard Algae in your tank, and if this happens, there are a few ways you can get rid of it.

Hydrogen Peroxide for Black Beard Algae

Hydrogen Peroxide is an effective way to treat Black Beard Algae. It can be purchased over the counter at most drugstores, and is a great thing to keep on handy for owners of aquariums.

If you suspect your plants, decorations, or aquarium equipment have Black Beard Algae, you can take them out and soak them in a bath of three percent Hydrogen Peroxide for around three minutes undiluted. After the three minutes is up, you simply just rinse everything off thoroughly in freshwater to remove the Hydrogen Peroxide.

If removing the affected items is not an option for you, you can treat your whole tank with Hydrogen Peroxide. Use 10mls of undiluted three percent Hydrogen Peroxide per 15 gallons in your tank. You can add the Hydrogen Peroxide to your tank by the pump so that it gets evenly distributed through your tank. Within a few days, you should notice the Black Beard Algae in your tank beginning to fade in color. It should die off in a month or so, and if not, it is safe to repeat this process over again. If the algae is stubborn, and not dying off, you can use a slightly higher dosage rate.

During this process, you may notice some of your plants changing color, but this is fine, and they should return back to normal after some time. Hydrogen Peroxide shouldn’t affect any fish in your aquarium, but you can remove them from the tank you are treating for peace of mind.

Flourish Excel for Black Beard Algae

The main compound of Flourish Excel (Glutaraldehyde) is used in the agriculture industry as pesticide, and it is used to disinfect and sterilize heat-sensitive equipment. Using Flourish Excel can be another method of removing Black Beard Algae from your aquarium. Flourish Excel is basically liquid carbon, and is a good alternative to a CO2 injection.

CO2 helps plants absorb nutrients more effectively. To use Flourish Excel in your tank, you basically have to overdose the tank to treat it. Overdosing your aquarium with Flourish Excel could potentially be harmful to your fish, and kill off your more sensitive aquarium plants.

There are many things you have to consider if you are going to use Flourish Excel in your aquarium to rid it of Black Beard Algae.

What to Consider When Using Flourish Excel for Black Beard Algae
Water volume of your tank

It is important to know the water volume exactly, so that you know how much to put into your aquarium. It is even more important to know in smaller tanks, because their ecosystems are so fragile. You may want to start with a dose slightly under the recommended amount for a smaller tank.

Types and amount of plants

For aquariums with few plants, the recommended dose will kill them off, but for a more heavily planted setup, you may need to use more than the recommended dose. This can make dosing your aquarium with Flourish Excel more difficult.

Aquarium lighting

Keeping your lights on in your aquarium for more than ten hours a day will help the algae grow, and it will grow with more light even though you are treating the tank with Flourish Excel. It is a good idea to use a timer for your aquarium to regulate the light even when you are not home, or able to.

It can be difficult to treat your tank with Flourish Excel, since it heavily relies on knowing the exact water parameters and balance of nutrients in your tank.

API Algae for Black Beard Algae

API Algaefix is not an effective way to rid your tank of Black Beard Algae, as it only works on green algaes. Black Beard Algae belongs to the red algae family, and it is important to know that it works by using surfactants which will make it hard for your fish to breathe. Even though it can be used effectively for other algaes, it is not recommended that API Algaefix is used to rid your aquarium of Black Beard Algae.

Fish Laboratory

With decades of collective fishkeeping experience, we are happy to share the fish care tips that we've picked up along the way. Our goal at Fish Laboratory is to keep publishing accurate content to help fishkeepers keep their fish and aquarium healthy.

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