Blackbeard Algae in Aquarium, Causes & How to avoid it?
Have you ever seen this unsightly black fuzz developing on the ends of plant leaves or the hardscape of your aquarium? If so, it’s probably black beard algae, sometimes referred to as black brush algae (BBA). Black algae in the fish tank are undoubtedly one of the most difficult forms of algae we encounter when maintaining freshwater fish, but don’t give up!
Although getting rid of it could be a little challenging, it is not impossible. In this essay, we’ll go over what exactly this black algae is, how to prevent it, and how to get rid of it from the aquarium.
What is Blackbeard Algae?
Aquarium algae often seen is called Black Beard Algae. It is a member of the red algae family and goes by the names brush algae, black brush algae, and occasionally plain BBA. There’s a strong likelihood that the algae in your tank are Black Beard Algae.
Although it may grow on nearly any surface in the aquarium, black beard algae frequently grow on the leaves of slow-growing aquarium plants. It is composed of tufts of thick patches or extremely fine threads. It got its name because it has a beard-like appearance. Even while it frequently has a black coloring, it can also appear as brilliant green, blue-green, or blackish green.

Algae of the Black Beard kind are widespread. Short fibers first appear in a tiny region, but if left uncontrolled, they will gradually lengthen. Usually, it begins to develop on the leaf margins before spreading to cover the entire leaf.
Neither do black beard algae deprive plants of nutrition or emit poisons into the water. If it totally envelops the plant, it might kill it. The plant would be unable to use the light for photosynthesis if it were covered. A surplus of black beard algae can also cause water imbalances, which put fish in the afflicted aquarium in danger.
If you notice a little number of black beard algae in your tank, it might not first seem to be a big concern. But before it worsens, the issue must be resolved right away. It may take over an aquarium if left unchecked and is quite difficult to physically remove. They are also, to put it mildly, rather unattractive.
What are the Causes of Blackbeard Algae?
1. Aquarium imbalance: Like all other algae, BBA grows primarily as a result of an aquarium imbalance. The presence of too many nutrients is most likely to blame for this imbalance. The extra nutrients will be used by the black algae to fuel its growth and distribution throughout the tank. Inadequate water quality, poor upkeep, using too much fertilizer, low or variable CO2 levels, too much light, or a combination of all of these factors can result in black beard algae.
2. Dirty/uncleaned Tank: In a tank that hasn’t been regularly cleaned, a lot of organic waste can accumulate. These organic materials break down and release nitrates into the water, which are used by both algae and living plants to develop. It’s crucial to remember that overfeeding fish or having an aquarium with too many fish can result in more waste being produced in the tank.
3. Too Much Light: When there is too much aquarium light, black beard algae frequently appears. It frequently thrives and expands swiftly in conditions of high intensity or prolonged light. It could be a good idea to relocate the tank or cover it with a shade if it is exposed to direct sunlight. Installing a light timer could be a smart option in order to manage the length of light that the aquarium gets. The amount of time the aquarium receives each day can be reduced to delay or even halt the growth of the algae. Consider gradually lowering the amount of light the tank receives from 12 to 8 hours each day if it now receives 12.
4. Low Carbon Dioxide Levels: The majority of the time, a tank with BBA has either no CO2 or variable CO2 levels. BBA can extract the carbon they need from hydrogen carbonate considerably more easily than any other aquatic plant in the tank if there is a CO2 shortage. To further clarify, black algae have the ability to separate the carbon from the hydrogen carbonate ion, which results in the production of hydroxide ions that raise pH. The algae utilize the calcium carbonate that precipitates as a result of biogenic decalcification to strengthen their cell walls. Unfortunately, this makes it harder to remove the algae and harder for animals that eat algae to digest it.
How to get rid of Blackbeard Algae?
In an aquarium, there are various techniques to get rid of black beard algae. Just keep in mind that these are merely short-term fixes, and the algae will probably continue to appear until the underlying issue is fixed. It is highly recommended that you review your fertilizer application plan, lighting schedule, maintenance schedule, etc. Identify the cause of the imbalance in your tank as best you can.
1. Hydrogen Peroxide
You may accomplish this by using a typical over-the-counter peroxide (3 percent ). This technique is frequently employed to treat fresh seeds for fungus just before germination. Remember that even the softer living plants, such as Japanese moss balls and Anubis, can sustain harm.
I advise using hydrogen peroxide to a water solution of 1:3 for plants that are more delicate. Your plants will be spared by the weaker solution in this manner, but it can take more than one plunge to get rid of the hair algae.
Anyhow, given that you’ll get rid of the black beard algae, it’s worth taking the chance. Even bleach at a 1 to 20 ratio will work if all you have are plastic plants, while peroxide can also do the trick. Use a timer and soak all other afflicted décors for two to three minutes before giving it a thorough washing.
The benefit of using peroxide is that it almost leaves no trace and allows you to immediately reintroduce your aquarium’s rock and plants. Although bathing in pure peroxide may seem a bit extreme, in my experience, black algae are quite difficult to get rid of. It won’t be enough to just add a few tablespoons of peroxide to the water in your fish tank.
2. Liquid Carbon additives
Black algae can be controlled by applying liquid carbon products to plants or other objects, but they may also be used to eradicate it once it has invaded them. Seachem’s Flourish Excel liquid carbon is a well-liked product. You have two choices when using liquid carbon: spot treatment or double dose in a different container.
If you are unable to remove the BBA-contaminated plants or other items from the tank, the simplest method to cure your tank is to spot-treat the BBA. Simply use a pipette or dropper to apply liquid carbon to the black algae to achieve this. Make sure you don’t fill the tank with too much additive.
If you can get the infected plants and hardscaping out of the tank, do these actions:
- Add twice as much as is advised based on the volume of water in the container, then leave them there for 24 hours.
- After the first 24 hours, replace all of the water and give the plants another 24 hours in the freshwater.
- Before putting everything back into your aquarium, go through the entire process one more time.
This ought to make the BBA obsolete. Research the plant’s susceptibility to liquid carbon before using this technique on it. Some plants, including Crypts and Vallisneria, are sensitive to these kinds of compounds and may be injured as a result.
3. Black Algae Eating Fish
BBA consumption by a few aquatic creatures has been documented. Perhaps the most suitable fish for the job is the Siamese Algae Eater. They are notorious for eating black algae as well as other kinds of algae. One aspect of these fish that could bother you is that when they become older, they could get up to 6 inches long. Other organisms that eat black beard algae include Amano shrimp, nerite snails, and Florida flagfish.

What is the Prevention of Blackbeard of Alage?
You probably already know the answers to those questions if you’ve read this far. But it’s vital to follow this checklist once you’ve defeated the unwelcome guest. Any favorable conditions WILL be advantageous to black beard algae.
In order to prevent BBA from ever returning to your aquarium, I strongly encourage you to pay great attention to the following:
1. Stabilizing lighting and Co2
BBA, like many algae, loves lots of light. Your aquarium’s Black Beard Algae may be receiving food from a bright light source or one that has been on for a long period, which may hasten its growth. Use a dimmer to decrease the amount of time your aquarium is lighted (we advise no more than 6 to 8 hours each day) and/or the brightness of the light.
Black Beard Algae can be brought on by low or variable CO2 levels, as was previously described. It’s critical to stabilize the CO2 levels in the tank so that it operates consistently for the same period of time and at the same BPS, in addition to raising your tank’s existing low CO2 levels. Use a drop checker to simply keep track of the CO2 levels in your aquarium.
2. Maintenance
The need for routine water changes cannot be emphasized enough! In order to maintain a healthy balance in the tank, we advise weekly water changes (or twice weekly if you are experiencing excessive ammonia levels). Simply substituting the “old” water, which can be full of nitrates, with clean water, will help lessen the number of nitrates and other nutrients in the water.

Most importantly, it’s crucial to undertake maintenance, including manually removing the BBA. Infected leaves can be removed or trimmed off to stop them from degrading and dispersing additional ammonia and algal spores into the water. Regular gravel vacuuming also prevents an excess of nitrogen from entering the system by removing food scraps and fish waste.
3. Cleaning tools after Maintenance
It’s crucial to thoroughly clean your aqua-scaping equipment if you have many tanks. Always clean your instruments after conducting any type of maintenance before using the same tools in another tank if you have this difficult-to-remove algae in one aquarium. This is the quickest method for Black Beard Algae—or any kind of algae—to spread and manifest itself unexpectedly in a tank that was previously algae-free.

The Bottom Line on Blackbeard Algae in Aquarium
As mentioned above, black beard algae pose no threat to your fish. That being said, it has the potential to harm your aquarium plants. If BBA spreads far enough to cover a plant’s leaves entirely, the plant can effectively “suffocate” and perish from a lack of nutrition and light.