Quick Answer
Black beard algae grows as dark tufts on hardscape, leaf edges, and slow-flow areas. It is stubborn, and it usually points to unstable CO2, organics, or long-term imbalance rather than a single quick cause.
Care and Setup Notes
- Remove badly affected leaves instead of trying to save every leaf.
- Improve circulation around dead spots and keep filters clean.
- Avoid dramatic chemical fixes unless livestock safety is fully considered.
What to watch
Use this page as a planning profile, then match the advice to your exact tank size, livestock, temperature, filtration, and water test results. If livestock are already stressed, test ammonia, nitrite, nitrate, pH, and temperature before making big changes.
Image: Wikimedia Commons fish photo used as contextual aquarium reference