How to Quarantine New Fish

Setting up a quarantine tank (QT) for saltwater fish helps protect your display tank from diseases like marine ich, velvet, or brooklynella. Quarantining ensures new fish are healthy before adding them to your reef or fish-only tank.

What You Need for a Saltwater Fish Quarantine Tank

1. Tank:
• 10-20 gallon tank for small fish; 30+ gallons for larger or multiple fish.
• Glass, acrylic, or even a plastic tub can work temporarily.
2. Heater and Thermometer:
• Maintain a stable temperature of 77–79°F (25–26°C).
3. Filter:
• A sponge filter (pre-seeded in your main tank) provides biological filtration.
• Hang-on-back (HOB) filter for additional water movement and filtration.
4. Powerhead:
• Provides water movement, essential for fish health and oxygenation.
5. Air Pump (Optional):
• Drives the sponge filter and increases oxygenation.
6. Ammonia Alerts:
• Use an ammonia alert badge to monitor ammonia spikes, as quarantined fish produce waste.
7. Light:
• Use a simple light—no need for reef-grade lighting. Keep it on a normal day-night cycle to reduce fish stress.
8. PVC Pipes or Decorations:
• Provide hiding spots to reduce fish stress. Use PVC elbows or fittings, which are easy to sterilize.
9. Test Kits:
• Ammonia, nitrite, nitrate, and pH test kits to monitor water quality.
• Refractometer to ensure stable salinity (1.024–1.026 SG).
10. Medication (On Hand):

• Copper Treatment (e.g., Cupramine): For marine ich and velvet.
• PraziPro: For flukes and internal parasites.
• Metronidazole: For bacterial infections and brooklynella.
• Seachem Prime: Detoxifies ammonia in emergencies.

Step-by-Step Process to Set Up and Use a Fish Quarantine Tank

1. Set Up the Quarantine Tank

• Install equipment: Add the heater, filter, powerhead, and PVC pipes to the tank.
• Fill with saltwater: Use RO/DI water mixed with salt to 1.024–1.026 SG.
• Seed the sponge filter:
• Place the sponge in your display tank for 1–2 weeks before setting up the QT. This will establish beneficial bacteria.

2. Acclimate Fish to the QT

• Float the bag in the QT for 15-20 minutes to match temperatures.
• Drip acclimate the fish for about 45 minutes to gradually equalize salinity and water chemistry.

3. Monitor Fish for Stress and Disease

• Observe fish closely for signs of disease:
• White spots: Marine ich (Cryptocaryon)
• Dust-like coating: Velvet (Amyloodinium)
• Excess mucus or labored breathing: Brooklynella

4. Use Preventive Treatments (Optional but Recommended)

• Day 1–7: Treat with PraziPro to eliminate flukes and internal parasites.
• Day 8+: If no signs of ich or velvet, continue observation or perform a second PraziPro dose.
• If ich or velvet is detected:
• Use a copper treatment (e.g., Cupramine). Monitor copper levels with a test kit to maintain the correct dosage.

5. Maintain Water Quality

• Daily Testing: Check for ammonia, nitrite, and nitrate levels.
• Water Changes: Perform 10-20% water changes every few days or as needed.
• Use Seachem Prime to detoxify ammonia if needed between water changes.

6. Keep Fish for 2–4 Weeks

• Quarantine fish for a minimum of 2–4 weeks.
• If diseases are detected, extend the quarantine until the fish are disease-free for at least 2 weeks without medication.

7. Transitioning to the Display Tank

• Acclimate the fish to the display tank’s water chemistry using the drip method.
• Ensure no new fish are added to the display tank during the quarantine period to avoid cross-contamination.

Tips for Success

• Keep QT tools separate from the display tank to prevent contamination.
• Use bare-bottom tanks for easy cleaning.
• Monitor fish behavior daily for signs of stress or illness.
• If a fish dies, sterilize the QT with bleach and start fresh before using it for another fish.

By following these steps, you'll minimize the risk of introducing disease and keep your main tank safe and healthy. Quarantine is essential for any new fish to ensure the long-term success of your saltwater aquarium.