The term “quarantine aquarium” and “quarantine tank” (often abbreviated as “QT”) refers to a separate tank set up specifically for isolating new or sick fish before introducing them to a main or display aquarium. The purpose of a quarantine aquarium is to prevent the spread of diseases, parasites, and other pathogens that could potentially harm the existing fish population in the main tank.

Aquarists, as a group, all understand the inevitability of fish becoming ill.  They understand that the water in the aquarium is teeming with pathogens.  The job of the aquarist is to stay ahead of any pathogen population in the aquarium.  Exchanging water, replacing filters, adding flora, and removing sick or dying fish is just part of the whole aquarium experience.

The aquarist is in a constant battle with pathogens and must remain vigilant to not only maintain a healthy water environment, but act proactively to prevent potential introductions of harmful pathogens.

One of the many tools available to the aquarist in support of their healthy tank regimen is the quarantine tank.  The quarantine Tank (QT) is typically a separate tank that is able to support aquatic life.  Often it has less volume that the production tank, although volume has no bearing on it’s effectiveness.

The QT has many uses for the aquarist.  Here are some key features and reasons for having and using a QT.

Isolation: A quarantine tank provides a controlled environment where new or sick fish can be observed for signs of disease or stress. This isolation period allows any potential issues to be addressed before the fish is introduced to the main tank.

Medication: If a fish shows signs of illness, it’s easier and often more effective to treat the fish in a smaller quarantine tank than in the main aquarium. This also prevents the medication from affecting healthy fish or the biological balance of the main tank.

Acclimation: New fish can be acclimated to the water parameters of the main tank while in quarantine, reducing the stress of transitioning.

Size: Typically, a quarantine tank is smaller than the main production tank. It doesn’t need to be as large because it’s not meant for long-term housing. A common size is 10-30 gallons, but the size can vary based on the size and number of tank occupants being quarantined.

Equipment: Quarantine tanks are usually simpler in setup than main tanks. Essential equipment includes a heater, filter, and aeration device. It’s often advised to avoid using substrates or decorations that could harbor pathogens.

Duration: The length of time an occupant should be quarantined varies, but a common recommendation is 2-4 weeks. This time frame allows for observation and ensures most diseases or parasites manifest and can be treated.

Water Quality: Regular water changes and monitoring of water parameters (like ammonia, nitrite, nitrate, pH, and temperature) are essential to maintain a healthy quarantine environment.

Regular Observation: During the quarantine period, fish should be observed daily for any signs of stress, disease, or abnormal behavior.

Setting up and maintaining a quarantine aquarium can seem like an additional chore, but the benefits of preventing potential outbreaks of disease in the main tank make it a worthwhile investment for serious aquarists.

Maintaining a quarantine tank involves several critical steps to ensure it serves its primary purpose: to prevent the introduction of diseases or parasites into the main aquarium. Here’s a rundown of what’s involved in maintaining a quarantine tank:

Setup: Before introducing any new fish or invertebrates to the QT:

• Ensure the tank is clean and free from residues.
• Fill the tank with water, preferably water from the main tank (to ensure similar water parameters).
• Set up essential equipment like heaters, filters, and aerators.

Water Parameters: Monitor and maintain water parameters regularly.

• Check for ammonia, nitrite, nitrate, pH, and temperature.
• Perform regular water changes to keep the water clean, especially since quarantine tanks are typically smaller and can accumulate waste faster.

Equipment Maintenance:

• Clean and maintain equipment like filters and heaters to ensure they work efficiently.
• Avoid using equipment from the quarantine tank in the main tank (and vice versa) to prevent cross-contamination.

Tank Cleaning:

• Regularly clean the tank’s interior surfaces to remove algae or biofilm.
• Perform a thorough cleaning after each quarantine period, especially if there was a disease outbreak.
• Use a mild bleach solution 1:10 (10%) to clean an emptied tank.  Many pathogens exist as cysts able to survive periods of no water.  A bleach solution is very effective.  Fill the tank and dilute it 10% with household bleach.  Let it sit several hours then empty and rinse, and thoroughly dry.

Hygiene:

• When handling anything inside the quarantine tank, wash your hands before and after to prevent cross-contamination.
• Use separate nets, siphons, and other tools exclusively for the quarantine tank.

Biosecurity:

• If possible, maintain the quarantine tank in a separate location from the main tank to minimize the chances of cross-contamination.
• Be cautious when introducing plants, decorations, or substrates from other sources, as they can also carry pathogens.

Often there is no warning before a tank occupant becomes ill.  Having a ready QT with good water parameters can make the difference between saving an occupant or not.

A good practice is to keep the QT active with fish at all times.  Keeping an active bioload with fish will help to maintain a healthy bacteria load and nutrient load in the water.  A hanging filter is all that is needed for the QT, and having active biology in place in the filter will lessen the shock a production tank occupant will experience when being moved to the QT.

Do not populate the QT with expensive fish.  It may be necessary to treat the water and the maintenance fish may not survive a water treatment regimen.

Additionally, when introducing a new occupant for observation, the occupant may be harboring an infectious pathogen that can infect the maintenance fish resulting in poor outcomes.

Many aquarists use the QT as a location to grow plants away from the hungry production tank occupants.  This is considered a good practice among aquarists.  Be certain to add an aeration device to increase the CO2 in the QT – your plants will thank you.

To learn more about the Quarantine Tank and how to manage it successfully, visit the links below.