Quick referenceTrichodina is a saucer-shaped protozoan parasite that triggers excess slime coat, flashing, and respiratory distress. Treat with formalin or salt for freshwater, copper for saltwater.
Symptoms
Excess slime coat (cloudy white film)
Scratching/flashing
Rapid breathing
Color fade
Frayed/torn fins
Lying on bottom
Cause
Trichodina protozoa attach to gill + skin surfaces. Trigger: poor water quality, stressed fish, recent shipping. Healthy fish generally clear infections themselves.
Treatment options
Aquarium salt (FW). 1 teaspoon per gallon. Dissolve fully in dechlorinated water before adding. Maintain for 7-10 days. Do partial water change at 50% to remove.
Formalin / ParaGuard. Effective freshwater + saltwater. Seachem ParaGuard at standard dose for 2 weeks. Provides best clearance.
Copper (SW). For marine trichodina. 2.0 ppm Cu using Cupramine or Copper Power. 14 days in QT only - copper kills inverts.
Improve water quality. Often fixes the underlying cause. Test ammonia + nitrite + nitrate. Daily 25% water changes during outbreak.
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
Maintain stable water parameters. Don't overstock. Quarantine new fish 30 days. Avoid stressing fish (sudden parameter swings, aggressive tankmates, shipping shock without acclimation).
Fatality + outcome
Low if treated early. Stressed/weak fish die from secondary respiratory infections; healthy fish in clean water clear it without medication.