Green Algae
Spirogyra
Spirogyra spp. (commonly associated)
A softer, stringier form of filament algae that can form long bright-green strands in the water column and around plants.
Quick facts
- Category
- Green Algae
- Organism group
- Green Algae
- Growth form
- Filament
- Primary color
- Bright Green
- Secondary color
- Light Green
- Attachment
- Weak
- Removal difficulty
- Moderate
Identification
Long, soft, sometimes slimy bright-green filaments that stretch and wave more than they branch.
- Growth form: Filament
- Primary color: Bright Green
- Secondary color: Light Green
Looks like: Compared with Rhizoclonium or Cladophora, Spirogyra usually looks softer, cleaner, and more string-like than wiry or fuzzy.
Where it appears
Typical affected areas
- On Plants
- On Hardscape
Common contexts
- New Tank
- Too Much Light
- Nutrient Imbalance
Causes
Shows up when fast-growing green filaments gain a head start over plant competition.
Most common triggers
- Young Tank Instability
- Excess Light
- General Nutrient And Carbon Imbalance
Root cause note: In hobby practice, Spirogyra is one of several filamentous algae labels rather than a guaranteed precise diagnosis.
Nutrient relevance
Balance relevance: High
Related nutrient issues
- General Imbalance
- CO2 Instability
Treat it like a filament outbreak: improve growth conditions rather than relying on one-off removal alone.
Correction hint: Reduce excess light and stabilize plant nutrition before expecting lasting improvement.
Treatment
Quick action: Manually wind out the longest strands and reduce the factors that let filament algae outpace plants.
Consistent maintenance and stronger plant competition work better long term than repeated emergency cleanups.
Manual removal: Remove gently so the strands do not fragment across the tank.
Difficulty: Moderate
Prevention
Keep the tank stable and avoid pairing strong light with weak plant uptake.
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.