🌿 Hair Algae (Filamentous Green Algae)
Scientific Name: Derbesia spp., Cladophora spp.
Common Name: Hair Algae, Green Hair Algae
Appearance: Stringy, green tufts on rock, powerheads, and overflow boxes
Reef Safe: ❌ Unwanted pest
Temperament: Aggressive and fast-growing
Diet: Photosynthetic – feeds on excess light and nutrients
Tank Role: Unwanted algae that outcompetes coral for light and flow
Description
🔍 Description:
Hair algae are one of the most common and frustrating algae in reef tanks. These fine, filamentous green strands grow in high-nutrient environments and quickly cover rock, frags, and equipment. If left unchecked, they block flow, reduce oxygen at night, and choke coral colonies.
Why it Appears
✅ Why They Appear:
Excess Nutrients: High phosphate and nitrate
Overfeeding & Dirty Filters: Fuel algae blooms
Low Grazer Density: Inadequate cleanup crew
Weak Flow: Dead spots allow buildup
Best Predator
🧽 Best Cleanup Crew for Hair Algae:
Trochus & Turbo Snails – heavy-duty grazers
Emerald Crabs – tug strands from rock
Tuxedo Urchins – consume stubborn patches
Mexican Turbo Snails (for large tanks)
Notes
⚠️ Notes for Success:
Manual Removal Helps: Use toothbrush or tweezers
Control Lighting: Reduce photoperiod during outbreaks
Check RO/DI Water: Poor source water feeds algae
Run GFO or Carbon: Helps reduce nutrients
Pro tip
🧠 Pro Tip:
Hair algae is a symptom of imbalance. Attack it with nutrient export, flow, and a solid CUC all working together.