How Long Should I Quarantine New Fish?
Quick Answer
Quarantine new fish for 4-6 weeks minimum. This allows time for diseases like ich and velvet to show symptoms and be treated before introducing fish to your display tank.
The standard quarantine period for new fish is 4-6 weeks. This timeframe allows most common diseases to manifest and be treated in isolation before the fish enters your display tank, protecting your existing livestock from potentially devastating outbreaks.
Why Quarantine Is Essential
Fish from any source—even reputable sellers—can carry parasites and diseases. Common reef tank diseases include:
- Marine Ich (Cryptocaryon): White spots, rapid breathing, scratching against rocks
- Marine Velvet (Amyloodinium): Gold dust appearance, extremely lethal if untreated
- Flukes: Gill and body parasites causing irritation
- Brooklynella: Especially common in clownfish
- Internal parasites: May not show symptoms immediately
Once these diseases enter a reef tank with live rock and corals, they're nearly impossible to eradicate without completely breaking down the system. Prevention through quarantine is far easier than treatment.
The 4-6 Week Timeline
Here's why this duration matters:
Weeks 1-2: Observation
Watch for signs of stress or disease. Allow fish to recover from shipping and adjust to eating prepared foods. Many parasites and diseases will show symptoms during this period.
Weeks 3-4: Prophylactic Treatment
Many experienced reefers run preventive treatments during quarantine:
- Copper treatment for ich and velvet (not for sensitive fish)
- Praziquantel for flukes and internal parasites
- Observation for any other issues
Weeks 5-6: Final Observation
After treatment, continue observing to ensure the fish is eating well, displaying normal behavior, and showing no symptoms. This buffer period catches any issues that may have been suppressed.
Setting Up a Quarantine Tank
A quarantine tank doesn't need to be elaborate:
- Size: 10-20 gallons works for most fish
- Filtration: Sponge filter or HOB with established media
- Heater: Match your display tank temperature
- PVC fittings: Provide hiding spots without porous materials
- Bare bottom: Easier to clean and observe
Important: Don't use live rock or sand in quarantine tanks—they absorb medications and can harbor parasites.
Can I Skip Quarantine?
It's tempting, especially when you've waited weeks for that perfect fish to arrive. But consider the consequences:
- A single ich-infected fish can spread the disease to every fish in your tank
- Treating a display reef is extremely difficult (copper kills invertebrates)
- Fish losses can cost far more than a simple quarantine setup
- Watching your established fish die is heartbreaking
The few weeks of patience during quarantine is nothing compared to the months of dealing with a disease outbreak.
What About Corals and Invertebrates?
Corals and invertebrates can carry fish parasites in their water, even though they don't get sick themselves. Many reefers quarantine corals for 72 days (the ich life cycle without fish hosts) or simply accept the risk, since treating display tank outbreaks is the alternative anyway.
For new corals, a coral dip upon arrival helps remove pests, but won't eliminate fish parasites from the water.
Track Your Quarantine
Use the ReefBay app to set reminders for medication schedules, feeding times, and the end of your quarantine period. Consistent tracking helps ensure you don't rush fish into your display prematurely.
Was this helpful?
