Black Beard Algae

Audouinella sp.

Also known as BBA, Black Brush Algae

Plantae›Rhodophyta›Florideophyceae›Acrochaetiales›Acrochaetiaceae

📍 Worldwide in freshwater streams

Dense, dark grey-to-black tufts that cling stubbornly to plants, hardscape, and equipment. One of the most frustrating nuisance algaes for planted tank keepers. Caused by CO₂ fluctuation and low or inconsistent carbon dioxide levels. Spot-treat with liquid carbon (Excel) or hydrogen peroxide.

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Quick Facts

role: nuisance
cause: CO₂ fluctuation, low flow
control: stable CO₂, liquid carbon spot-treatment, Siamese Algae Eater

Water it likes

ph: 6.5–8.0
hardness: 4–18 dGH
temperature: 68–81°F (20–27°C)

Legality

No state or federal restrictions on record for this species.

Not legal advice, and possibly incomplete or out of date. Rules vary by state and locality and change over time — always confirm the current regulations with your state wildlife or agriculture agency before buying, keeping, or shipping this species.