stone covered with black beard algae

How To Prevent Your Tank From Getting Black Beard Algae

Many different forms of algae can grow in aquariums, spoiling the look of your setup, clogging filters, and obscuring the glass. Black beard algae is a particular nuisance, as it’s unsightly and very difficult to get rid of.

This article tells you everything you need to know about removing black beard algae from your tank.

What are Black Beard Algae?

aquarium plants with black beard algae

Black Beard algae is an extremely tenacious species of algae that can be challenging to get rid of. The algae grow on the leaf edges of slow-growing plants, such as Java fern and Anubias. Once attached to the leaves, the algae are incredibly difficult to shift completely. In severe cases, the algae will block the plant’s access to light and nutrition, ultimately killing it.

You also see Black Beard algae growing on aquarium equipment, decorations, bogwood, rocks, and even gravel grains in the substrate.

Black Beard algae are also known as Brush algae. The organism’s scientific name is Audouinella, and it belongs to the family of red algae. The algae’s natural color varies from very dark green, through gray, to a deep black. The algae grow in furry tufts that resemble a beard or brush, hence the organisms common name.

What causes Black Beard Algae?

There are several causes of Black Beard algae, including excessive light in the tank, low or fluctuating levels of CO2, high levels of pollutants in the water, and a lot of floating detritus in the tank.

However, the main cause of Black Beard algae’s outbreaks is low or unstable levels of carbon dioxide in the water. How so? When CO2 levels are unstable or very low, live plants in the aquarium cannot utilize the light and nitrate fertilizers available to photosynthesize. Unfortunately, although that kind of environment is bad news for plants, it’s great for Beard algae.

Too much light

Like most plants and algae, Black Beard algae thrive when provided with plenty of light. The more light the organism receives, the quicker it will spread.

So, the longer you leave your tank lights on, the more the algae will grow. A quick fix is to reduce the amount of time that light shines onto your aquarium. By depriving the algae of light, you can stop it from growing or even eliminate it altogether if you use that tactic in combination with other eradication methods.

Try using a reliable aquarium timer that will turn your lights off and on automatically every day, so you don’t have the hassle of remembering to do so.

How do Black Beard Algae get into the tank?

Black Beard algae get into your fish tank in two ways. You may buy some new plants and put them into your setup, unaware that they are carrying tiny Black Beard algae spores that are not visible to the naked eye. These spores develop into the algae, which then becomes visible and spreads throughout the tank, given the right conditions.

Black Beard algae can also get into your aquarium as tiny free-floating strands in a bag with new fish. Once in the tank, the algae attach itself to a suitable surface and grow.

Are Black Beard Algae bad for your fish?

Black beard algae are not harmful to fish. In fact, many fish seem to enjoy hiding among the flowing mass of algae. Some aquarists actually encourage Black Beard algae’s growth on certain rocks and pieces of driftwood as it can look quite attractive when properly maintained and controlled.

How to remove Black Beard Algae

Although Black Beard algae are undoubtedly difficult to get rid of, it is possible to shift it, and there are several ways of doing so.

Trim plants

fishkeeper trimming aquatic plants with black beard algae

The most effective way to get rid of Black Beard algae from plants is to remove any infected leaves by trimming them off with aqua scaping scissors.

Clean decorations

You can remove the worst of Black Beard algae from solid objects in the aquarium by using an old toothbrush or wire brush to scrub the organism away. As you work, use a siphon to remove any detritus and algae that you dislodge so that it doesn’t float away to infect other parts of the tank.

Algae that attaches to the glass can sometimes be shifted by using a razor blade or plastic scraper. Again, be sure to siphon away the algae and waste as you work, and take great care not to damage silicon seals.

Bleach rocks and decorations

You can remove any infected rocks and decorations from the tank and immerse them in a bleach solution for a few minutes. Scrub the items to dislodge the algae before rinsing them thoroughly and returning them to the tank.

Paint the algae

Another way of dealing with Black Beard algae is to lower the water level beneath where the algae are growing. So, if you have an outbreak of algae growing on a rock, you can remove enough of the water in your tank to expose the algae to the air.

Measure out your usual daily dose of Seachem Flourish Excel but rather than pouring it into your tank, take a very small paintbrush and paint the undiluted liquid onto areas affected by algae. Leave the algae exposed for a minute or so, and then refill the tank as you would during your weekly water change regimen.

After a day or two, the Black Beard algae should turn pink and die off. Once that happens, take a scrubbing brush to remove as much of the remnants as you can.

Add algae eaters to your tank

You can let nature do the work by adding some algae eaters to your tank. Unfortunately, only a few fish eat Black Beard algae, including the Siamese Algae Eater (Crossocheilus siamensis) and the Florida Flag Fish. Do make sure that you buy the correct species. Many fish are sold under the name of Siamese algae eater but are actually a different species.

Shrimp also eat algae, and they will graze on Black Beard algae. However, shrimp usually don’t eat fast enough to really make a dent in the algae’s progress.

The main drawback to using algae eaters to control algae in your fish tank is that there’s no guarantee that the creatures will actually eat the algae!

Treat the tank with copper

If all other efforts to get rid of Black Beard algae fail, you can treat the tank with copper, following the manufacturer’s directions carefully. However, copper can have an adverse effect on some plants, fish, and invertebrates, and it must be used with caution.

Preventing Black Beard Algae

Now that you know how to identify and treat Black Beard algae let’s talk about how to prevent it from infesting your tank in the first place.

New plants

Never take plants from a tank that contains algae and introduce them to another algae-free tank.

When purchasing new plants, soak them for two to three minutes in a solution of 10% bleach to conditioned tap water to kill any algae before you put them into your tank.

New fish

Before putting new fish into your display tank, we advise that you quarantine them. That way, you can observe your new acquisitions to make sure that they’re disease-free and healthy. Also, if Black Beard algae are present in the water the new fish came in, it will be caught in the quarantine tank, rather than ruining your display tank.

When you transfer the fish to your main tank, always use a net so that now water enters the setup.

Improve water quality

Poor water quality encourages the growth of Black Beard algae and is very bad for your fish and other livestock.

Be sure to carry out weekly 25% water changes, rinse filter media in tank water every month to remove clogging and sludge, and change spent filter media when required. Vacuum the aquarium substrate weekly to remove detritus and waste and regularly monitor the water pH to avoid an overly acidic environment.

Boost CO2 levels

You can help to keep the tank environment unattractive to Black Beard algae by adding liquid carbon to the water every day. A good product to use for this purpose is Seachem Flourish Excel.

In conclusion

Black Beard algae is an unsightly menace that can quickly ruin your tank by attaching itself to plants and decorations. Although it is possible to get rid of Black Beard algae by using one or several of the methods outlined above, it’s best to prevent the problem in the first place.

Keep your tank clean and hygienic, take care when introducing new plants and fish, and don’t give your fish tank too much light.

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