Red Algae
Black Beard Algae
Audouinella spp. / Rhodochorton spp. (commonly associated)
A difficult red algae that grows as dark brushy tufts on leaves, hardscape, and equipment.
Quick facts
- Category
- Red Algae
- Organism group
- Red Algae
- Growth form
- Tuft
- Primary color
- Black
- Secondary color
- Dark Gray
- Attachment
- Strong
- Removal difficulty
- Hard
Identification
Dense dark gray, black, or reddish brush-like tufts, often on hardscape, filter outlets, equipment, and leaf margins.
- Growth form: Tuft
- Primary color: Black
- Secondary color: Dark Gray
Looks like: Usually denser and more clustered than staghorn algae, which tends to look more branching and horn-like.
Where it appears
Typical affected areas
- On Hardscape
- On Plants
- On Glass
Common contexts
- Low Flow
- Nutrient Imbalance
Causes
BBA often appears where organic loading, poor maintenance, unstable flow, or overstressed planted-tank balance work against healthy plant competition.
Most common triggers
- High Organic Pollution In Fish Heavy Tanks
- Muck Accumulation In Filter Or Substrate
- Red Algae Are Intensified By Micronutrient Or Iron Overdosing In Some Planted Tanks
Root cause note: This is one of the hardest aquarium algae types because it anchors strongly and is not favored by many grazers.
Nutrient relevance
Balance relevance: High
Related nutrient issues
- Iron Overdose Can Intensify Red Algae
- General Imbalance
- Organic Loading
In planted systems, red algae often points to imbalance rather than simply too many nutrients in a generic sense.
Correction hint: Do not only dose less; also clean trapped waste, improve flow, and stabilize plant growth.
Treatment
Quick action: Manually remove what you can and address organics, flow, and maintenance immediately.
Physical removal plus stability work is essential; localized carbon or peroxide-style spot treatment is often used carefully as a secondary tool.
Manual removal: Hardscape can often be spot-cleaned more aggressively than living plant leaves.
Difficulty: Hard
Prevention
Keep organics low, avoid neglected filters and substrate buildup, and do not overdrive a tank that is not metabolically stable.
This page is designed to help with visual identification first, then causes, treatment, and prevention. Actual algae pressure can vary depending on maintenance, livestock, plant mass, light, flow, and nutrient consistency.