Quarantine: the unsexy practice that saves your tank

Marine ich (Cryptocaryon irritans) and velvet (Amyloodinium) live in the parasitic life cycle of every store, every wholesaler, and every tank that hasn't been deliberately disinfected. Once they enter your display, they're nearly impossible to fully eradicate without removing all fish for 76+ days.

The single most important defense: quarantine every fish before it enters your display tank.

What you need

• A separate, bare-bottom tank (10–20 gallons works for most fish)
• A sponge filter that's been seeded in your display sump for 4+ weeks
• A heater
• A lid
• PVC pipe pieces for hiding
• Copper-based medication (Cupramine, Coppersafe) — for active treatment if needed
• A copper test kit

The basic protocol

1. Acclimate new fish to QT using drip method (~2 hours)
2. Observe for 14 days minimum, watching for white spots (ich), gold dust (velvet), labored breathing, scratching
3. If parasites appear: treat with copper at 2.5 ppm for 14 days; finish full treatment even if symptoms vanish
4. Prophylactic treatment (advanced): treat all fish with copper as a default, regardless of visible symptoms. Trade-off: more stress on the fish, but guaranteed display-tank health.

What you can never do

• Skip QT because the fish "looks healthy at the store"
• Treat the display tank with copper (it kills inverts and corals)
• Move equipment, water, or rocks between QT and display without disinfection

The compromise option

If you can't run a permanent QT, build a transfer tank protocol: tank-to-tank transfers every 72 hours for 12 days break the ich life cycle without medication. Less effective than copper for velvet, but better than no quarantine.

Quarantine is boring. It's the practice that keeps your $4,000 reef from becoming a $0 reef in three weeks.