Red Slime (Cyanobacteria)
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About this condition
A mass growth of cyanobacteria (blue-green algae) covering rocks and substrate with red or purple slime. It blocks light for corals and consumes oxygen in the aquarium.
Common symptoms
- Red to purple slime spreading over rocks and sand
- Foul odor
- Coral coverage
- Oxygen consumption
Common causes
- Excess nutrients (phosphate and nitrate)
- Insufficient water flow
- Old lighting
- Overcrowded stocking
Prevention (husbandry & daily care)
Proper nutrient management, adequate water flow, regular light replacement, avoid overcrowding.
Related species guide
→ Browse the species guide for this animalWhen to see a vet
Monitor; consult a specialist store if it worsensWhat can a specialist store do?
Consulting with an aquarium specialist provides guidance on testing nutrient levels and specific steps to restore overall tank balance.
Related columns
Other conditions in this animal
Coral BleachingConsider consulting a specialist store within a few daysRapid Tissue NecrosisConsult a specialist store or experienced keeper promptlyBrown Jelly DiseaseConsult a specialist store or experienced keeper promptlyFlatworm InfestationMonitor; consult a specialist store if it worsensTissue Recession (Polyp Recession)Consult a specialist store or experienced keeper promptlyNudibranch PredationConsider consulting a specialist store within a few daysAlkalinity Burn (KH Burn)Consider consulting a specialist store within a few daysMarine Ich / CryptocaryoniasisConsult a specialist store or experienced keeper promptlyMarine Velvet / AmyloodiniosisConsult a specialist store or experienced keeper promptlyBrooklynelliasis / Clownfish DiseaseConsult a specialist store or experienced keeper promptlyHead and Lateral Line Erosion (HLLE)Monitor; consult a specialist store if it worsens