Does Bleach Kill Black Beard Algae in an Aquarium? Safe?

Do you have black beard algae in your aquarium and you are wondering if you can use bleach to kill the algae?

Is bleach safe to use in your aquarium?  Find out below

Does Bleach Kill Black Beard Algae in an Aquarium?

Yes, Bleach is a quick and effective treatment for getting rid of black beard algae in your aquarium.

To ensure you get rid of all the algae, soak your affected aquatic plants in a 10 percent bleach solution for two to three minutes. Clean and rinse out thoroughly so the algae doesn’t return, and no more harm comes to your aquatic plants.

Does Bleach Kill Black Beard Algae in an Aquarium

Use this method sparingly, as not all aquatic plants are hardy enough to withstand bleach treatment without sustaining some damage to the leaves.

The rest of this article will tell you all you need to know about black beard algae and how to use bleach to eliminate this common pest from your aquarium.

How do you get rid of Black Beard Algae with Bleach?

Algae is carried through soil, so it’s most likely to come into your aquarium via your aquatic plants. Usually removing plants from the tank and applying a 10 percent bleach solution to the affected leaves works well.

Some aquarium owners report success by simply removing the leaves with black beard algae and allowing new, unaffected leaves to grow in their stead. While this method avoids any bleach damage to the plant, it’s easy to miss areas where algae is present, especially if the algae is still too minimal to be seen with the naked eye.

Sometimes the root cause of black beard algae in your tank can be difficult to pinpoint. In cases like these, it’s best to do the following:

  • Drain the tank
  • Remove everything from your tank (fish, plants, plastic plants, decor, rocks, etc.)
  • Soak everything in your aquarium (excluding fish) in a 10 percent bleach solution for 2 – 3 minutes
  • If you have sand instead of rocks as your substrate, throw out sand and replace
  • Fill empty aquarium with same 10 percent bleach solution and thoroughly scrub floor and sides of tank
  • Rinse tank, plants, and everything taken out of aquarium
  • Assemble aquarium as before
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Is Bleach Safe to Use in an Aquarium?

While bleach is safe for occasional aquarium use, using it too much can irreparably damage your aquatic plants. While thorough rinsing ensures that no bleach gets into your aquarium and harms your fish, the more you use bleach, the more you run the risk of contaminating your tank.

If you find you need to regularly rid your tank of black beard algae and other pests, experts recommend hydrogen peroxide as a safer alternative.

Can You Use Bleach to get rid of Black Beard Algae on Plants?

If the black beard algae is only present on your aquatic plants, then you can avoid fully disassembling your aquarium.

  • Prepare a 10 percent bleach solution
  • some experts recommend a 5 percent solution to minimize any damage to your plants from the bleach, especially if your plants aren’t as hardy
  • Remove affected plants from the aquarium
  • Submerge affected leaves into the bleach solution for 2 – 3 minutes
  • Alternatively, you can use a pipette to drip bleach solution onto the affected leaves
  • Rinse leaves thoroughly before placing plants back in aquarium



Hello, I'm Jason. I'm the guy behind I volunteer at my local fish shop and I created this site to offer tips and advice on the fish I care for.

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