Does UV Light Kill Black Beard Algae? {Is UV The Answer}

Ultraviolet lights are often used to sterilize aquarium tanks in order to kill unwanted bacteria and algae. However, UV light does not kill black beard algae which is a fuzzy red algae that can inhabit freshwater tanks.

UV lights are effective against phytoplankton, which are algae too small to see, as well as many kinds of green algae. Since black beard algae is technically a red algae, UV light has no detrimental effect.

In this article, we will cover the different things that will kill black bear algae as well as tips on how to prevent black bear algae from returning or establishing itself in your tank in the first place.

What Kills Black Beard Algae?

Black beard algae can be difficult to get rid of because it can get into the smallest holes and cracks. If you don’t eliminate all of it, black beard algae will return no matter how small of a piece gets left behind.

The first step to eradicating black beard algae is to select a method that will ensure the complete elimination of the problem.

Does UV Light Kill Black Beard Algae

One of the most common ways involves a hydrogen peroxide bath. Remove all infected décor from the tank and soak it in hydrogen peroxide to completely kill the algae.

Another method that is slightly less effective but does not involve chemicals, is placing infected decorations in a boiling hot water bath.

If you want to go a more natural route, you can use biological black beard algae elimination methods by introducing fish or invertebrates that eat the algae.

Amano shrimp and nerite snails are great for algae clean up and can get into the hard to reach spaces that the black beard algae tend to inhabit.

There are also a variety of fish species that are effective at eradicating black beard algae such as Florida flag fish, Chinese algae eaters, goodeids, flying foxes, rubber lip plecos, golden algae eaters, and Siamese algae eaters.

How to Prevent Black Beard Algae from Returning

If you have had a black beard algae infestation, the last thing you need is for it to return. Ensure that you use a clean up method that will eliminate all of the black beard algae or continue to keep it under control if it does return.

Another way to help discourage its growth is by lowering the phosphate levels in your aquarium tank. Black beard algae thrive on dead material and waste products that are rich in phosphate.

They also proliferate under low carbon dioxide conditions so increase the CO2 in your tank. This will also help your plant life thrive and produce more oxygen from photosynthesis.

Last of all, reduce the amount of time your aquarium is under the lights. Black beard algae thrive in high sunlight conditions so mitigate the amount of time your tank spends under the lights.

Having algae eating fish in your tank is the best way to not only get rid of but keep any future outbreaks of black beard algae under control.


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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