Quick referenceGlugea is a microsporidian parasite that forms visible white cysts in fish tissue. Untreatable; cull infected fish to prevent spread to tankmates.
Symptoms
White cysts visible under skin
Tumor-like lump
Color fade
Weight loss / sunken belly
Lethargy
Spinal deformity
Cause
Glugea microsporidia spores. Spread by ingesting infected fish or spores from feces. Often linked to live tubifex or contaminated frozen feed.
Treatment options
No effective cure. No medication treats microsporidia in fish. Fenbendazole (Panacur) shows mixed lab results but typically does not cure visible-cyst fish.
Cull infected fish. Most reliable response. Use clove-oil overdose euthanasia.
Sterilize tank. For severe outbreaks: euthanize stock, drain, 10% bleach 24h, rinse, restart cycle. Spores survive normal disinfection.
Strict quarantine. Quarantine survivors permanently if kept. Never mix with naive fish.
Always treat in a separate quarantine or hospital tank. Most medications are toxic to coral, invertebrates, and live rock biology. Consult an aquatic veterinarian for valuable fish.
Prevention
Avoid live tubifex. Cook frozen feeders/feed before use. Quarantine new fish 30 days. Buy from breeders, not pet-store discount tanks.
Fatality + outcome
High over time - cysts grow + crowd organs. Most infected fish die in 3-6 months.