Do Black Mollies Eat Black Beard Algae? (Finally Solved!)

Do Black Mollies eat Black Beard Algae? Yes, Black Mollies will eat Black Beard Algae. Black Mollies are one of the few fish that will actively eat Black Beard Algae. Black Mollies actually possess small teeth at the front of their mouths which they use to pull at the Black Beard Algae.

If you have been in fish keeping for any length of time, you will no doubt have found yourself battling against the dreaded Black Beard Algae. Black Beard Algae can be very tricky to get rid of. You may have heard that there are some fish out there that will eat Black Beard Algae.

What Is Black Beard Algae?

Eating Daphnia
Eating Daphnia

Black Beard Algae (which is also sometimes called Brush Algae), is a particularly difficult algae to get rid of. It grows in dense clumps or tufts of dark green to black, hair-like strands. Black Beard Algae grows on almost any hard surface including rocks, wood, and decorations. Black Beard Algae will also grow on the leaf edges of slow-growing plants such as Anubias or Java Fern.



What Causes Black Beard Algae?

Black Beard Algae is often introduced into the aquarium on new plants or potentially in the water in a bag of new fish from the local fish store. The smallest piece of Black Beard Algae can soon spread once it is introduced into the aquarium.

Once in the tank, low or unstable levels of CO2 will allow the Black Beard Algae to get a foothold. When CO2 levels in the tank water are low, plants in the aquarium can’t efficiently use the available nutrients or light to photosynthesis properly.

This leaves excess nutrients in the water which the Black Beard Algae will take advantage of. For this reason, people will often say ‘adding CO2 to your aquarium gets rid of Black Beard Algae’. Whilst not technically correct, in a roundabout way it does help by giving the plants in the aquarium the ideal conditions in which to grow and thrive.



How Can I Get Rid Of Black Beard Algae?

Whilst Black Mollies will have a good go at eating the Black Beard Algae, they won’t get rid of a large infestation without some help. To completely get rid of the Black Beard Algae you will need to start by removing as much from the aquarium as you are able to by either scraping, rubbing, or picking off the algae where you can.

Once you have removed as much as you can, consider adding as many fish and invertebrates that will eat the algae as your setup allows.

What Other Fish Eat Black Beard Algae?

Siamese Algae Eaters are well known in the freshwater fish keeping hobby for eating Black Beard Algae, as are Florida Flagfish. There aren’t very many other fish that are commonly available that will be interested in eating the algae.

Some local fish stores will keep Siamese Algae Eaters in their plant sales tank to remove any Black Beard Algae before it can establish itself.

Does Anything Else Eat Black Beard Algae

Amano Shrimp are well known for eating Black Beard Algae. You would however need an army of them to tackle a large outbreak of algae. Amano Shrimp are best used either before the Black Beard Algae becomes a problem (they will eat the ‘starts’ of the Black Beard Algae), or when you see the first signs of the algae taking hold.

How Can I Prevent Black Beard Algae Coming Back?

One of the best ways to prevent Black Beard Algae from coming back once you get rid of it is to add Amano Shrimp. Amano Shrimp will eat any small pieces of Black Beard Algae before they have a chance to really get growing.

Adding more live plants, and then feeding those plants with fertilizer will also help prevent Black Beard Algae coming back. I have a really good article about the best aquarium plants for beginners.

If you are very organized and patient you can have a separate quarantine tank to grow your aquarium plants in for a few weeks before you move them to your main aquarium so you can check they aren’t going to bring any Black Beard Algae in with them. I have to admit, I have never had the patience to do this!

Why Aren’t My Black Mollies Eating The Black Beard Algae?

If you have Black Mollies in your aquarium, but they aren’t tackling the Black Beard Algae, hold off feeding them for a couple of days. Just because Black Mollies WILL eat Black Beard Algae, it doesn’t necessarily mean it would be their first choice of food.

They would probably rather tuck into some nice live bloodworm or a mouth full of tasty pellets instead. By holding back the food for a few days, the Mollies will be inclined to go looking for something else to eat.

Can Black Mollies Survive Just Eating Black Beard Algae?

Black Mollies need a varied diet to grow and thrive. A Black Mollies Diet should be made up of a good quality pellet or flake food (check out my article on the amazing Bug Bites from Fluval) with the addition of some live or frozen food such as Bloodworms or Mosquito Larvae.

Do Black Mollies Eat Other Algaes?

Black Mollies will pick at other hair algae as well as the Black Beard Algae. You may have to hold off the food a little longer to convince them to move on to hair algae. Black Mollies won’t eat diatom algae or Green Spot Algae.

In Conclusion

Black Mollies will eat Black Beard Algae, providing they are hungry enough. If you have an outbreak in your aquarium, start by physically removing as much as you can. Depending on the size of the aquarium and the severity of the outbreak, you may need a small army of Black Mollies to get rid of it, but adding some Siamese Algae Eaters and Amano Shrimp to the aquarium, if your set up allows, will also help.

One Final Thing…

If you have found this article about Black Mollies interesting, why not check out my articles Can Black Mollies live in Cold Water, Why aren’t my Mollies Breeding, and Do Black Mollies Lay Eggs?


About the Author

I’ve been keeping, breeding, and showing tropical fish for nearly 30 years. Over that time I’ve done it all! I’ve had great success and I’ve made some really foolish mistakes (like the time I bought an Asain Walking Catfish). Read more…
Richard James
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