Green Algae
Oedogonium / Fuzz Algae
Oedogonium spp. (commonly associated)
Short green filaments that form fuzzy patches on leaves, hardscape, and sometimes glass.
Quick facts
- Category
- Green Algae
- Organism group
- Green Algae
- Growth form
- Fuzz
- Primary color
- Green
- Secondary color
- Yellow Green
- Attachment
- Moderate
- Removal difficulty
- Moderate
Identification
Small green hairs that stand individually or in light fuzzy patches rather than long strings.
- Growth form: Fuzz
- Primary color: Green
- Secondary color: Yellow Green
Looks like: Often confused with hair algae; fuzz algae is more isolated and less carpet-like, especially in earlier stages.
Where it appears
Typical affected areas
- On Plants
- On Hardscape
- On Glass
Common contexts
- New Tank
- Nutrient Imbalance
Causes
Very common in weeks 4–8 of young tanks and after nutrient balance slips in older setups.
Most common triggers
- Young Ecological Imbalance
- Carbon Deficiency
- Macronutrient Imbalance
Root cause note: Fuzz algae often reflects a tank that is close to balance but still not stable enough to fully outcompete opportunists.
Nutrient relevance
Balance relevance: High
Related nutrient issues
- CO2 Deficiency
- NPK Imbalance
Fuzz algae is commonly linked to carbon shortage and macronutrient imbalance in planted tanks.
Correction hint: Stabilize carbon and NPK before trying repeated harsh algae treatments.
Treatment
Quick action: Remove visible tufts manually and correct the imbalance instead of only cleaning surfaces.
Once plant growth improves, fuzz algae is usually easier to outcompete than red algae types.
Manual removal: Rub or trim affected spots before the fuzzy filaments thicken into denser growth.
Difficulty: Moderate
Prevention
Balanced nutrients, better carbon supply, and steady maintenance help prevent return outbreaks.
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.