What does Turf algae (Cladophora + filamentous greens) look like?

Thick green carpet on rocks. Dark green tufts on filter intakes. Fast spread (1-2 weeks).

How is Turf algae (Cladophora + filamentous greens) treated?

Manual removal + scrape: Scrub with toothbrush + magnetic algae scraper. Siphon out detached filaments before they decompose. Repeat weekly.

MIXED disease

Turf algae (Cladophora + filamentous greens)

Reviewed by the Fast Aquatics husbandry team · Updated May 2026

Quick referenceTurf algae is dense filamentous green algae that carpets rockwork + glass. Common in mature reef + planted FW tanks with high nutrients. Manual removal + algae-eaters + reduced light.

Symptoms

Thick green carpet on rocks
Dark green tufts on filter intakes
Fast spread (1-2 weeks)
Dense filaments difficult to remove
Smothers coral or low-light plants

Cause

Excess nitrate (>10 ppm) + phosphate (>0.1 ppm) + intense light. Common in tanks 6-18 months old as nutrients accumulate. Often introduced on hitchhiker rocks.

Treatment options

Manual removal + scrape. Scrub with toothbrush + magnetic algae scraper. Siphon out detached filaments before they decompose. Repeat weekly.
Reduce nutrients. Larger water changes (50% weekly), reduce feeding, add chaeto refugium (SW), add fast-growing stem plants (FW).
Algae crew (SW). Tangs (yellow, sailfin, hippo), urchins, foxface, large turbo snails. Mexican turbo eats most varieties.
Algae crew (FW). Amano shrimp, otocinclus, Siamese algae eater (true SAE), bristlenose pleco.
Fluconazole nuke. For severe outbreaks: 20 mg/gal fluconazole works well on bryopsis + green hair algae. Reef-safe but kills macroalgae too.

Always treat in a separate quarantine or hospital tank.

Prevention

Maintain nitrate <5 ppm reef / <30 ppm FW. Phosphate <0.1 ppm reef. Limit photoperiod to 8-9 hours. Clean filter media regularly.

Fatality + outcome

Not fatal directly. Outcompetes coral/plants for light + nutrients; kills sensitive species over time.

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Aquarium-keeping fundamentals

Whatever specific topic brought you here, four fundamentals govern long-term aquarium success: water quality, parameter stability, biological filtration, and species-appropriate husbandry. Skip any one and the others struggle to compensate.

Water quality: ammonia + nitrite at zero, nitrate under 30 ppm freshwater + 10 ppm reef. Test weekly with API or Salifert kits. Use our water parameter checker to score your readings against your tank type.

Parameter stability: stable wrong parameters beat fluctuating ideal parameters. Most fish tolerate a wide pH range if it's stable. Sudden swings of 0.4+ pH or 5+°F kill fish faster than chronic suboptimal values. Use temperature controllers (Inkbird) + automated dosing for consistency.

Biological filtration: the bacterial colony on your filter media + rock + substrate is the engine. Never replace all media at once. Use our filter turnover calculator to size correctly.

Species-appropriate husbandry: research adult size, territoriality, diet, and tankmate compatibility before purchase. Use our tank stocking calculator + compatibility guides.

Frequently asked questions

How long does an aquarium take to set up? 4-6 weeks for full cycling + first stocking. Use our cycle ETA calculator + how long does cycling take.

What's the best aquarium for beginners? 20-gallon long. Big enough for parameter stability, small enough for budget + space. See beginner picks.

How often should I do water changes? 25-30% weekly. See water change frequency Q&A + water change calculator.

Why does my fish keep dying? 5 leading causes: uncycled tank, wrong species pairings, no quarantine, undersized tank, neglected water-change schedule. See full diagnosis.