How do I quarantine new fish?

Reviewed by the Fast Aquatics husbandry team · Updated May 2026
Quick answer20-30 gallon QT, mature sponge filter, heater, dim light, no substrate. 30 days minimum observation. SW: 14 days copper + 2x prazi at days 1+14. FW: prazi (PraziPro) for flukes. Use our calculator.

Full answer

Proper quarantine prevents 95% of disease outbreaks - here's the protocol. QT setup: 20-29 gallon bare-bottom tank. Mature sponge filter (run in display 4+ weeks before stocking QT, or seed with established media). Adjustable 100W heater. Dim light. PVC pipe + ceramic flowerpots for hiding. No live rock, no plants, no substrate (medications + cleaning). Test kit on hand. Saltwater protocol (recommended): Day 1 = acclimate fish, dose Prazi (PraziPro) once. Day 1-2 = ramp copper to therapeutic 2.0 ppm Cu (use Cupramine or Copper Power, monitored with Hanna or Salifert Cu test kit). Day 14 = second Prazi dose. Day 14-16 = drawdown copper with Cuprisorb or carbon. Day 30 = if fish symptom-free for 7+ days, transfer to display. Freshwater protocol: Day 1-7 = API General Cure (prazi + metronidazole) for flukes + internal parasites. Day 8-14 = continue observation. Day 15 = Maracyn 2 if any bacterial signs. Day 28 = if clear, move to display. Tank Transfer Method (TTM, ich-only): 4 transfers between 2 sterile tanks every 72 hours. Breaks ich life cycle without copper. Why most people skip QT: takes time, costs ~$200 setup. Cost of skipping: tank-wide ich/velvet outbreak that kills 30-80% of stock. Use our QT timeline calculator to plan dates.

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