BestForPets is reader-supported. Your purchases via our links may earn us an affiliate commission at no extra cost to you. Our Affiliate Disclaimer

How To Properly Quarantine A New Fish (Guide)

Quarantining young fish is one of the most crucial, yet most frequently neglected, components of fishkeeping. It is essential to discuss why you should quarantine new fish and what you should do if you've already introduced new fish without quarantining them.

There are a few supplies you'll need to quarantine your fish, as well as a series of actions to follow. Let's get started by reading "How to Properly Quarantine a New Fish" on BestForPets (bestforpets.org)!

Why Should I Quarantine My New Fish?

Understanding why you must quarantine new fish is the first step in quarantining new fish. Quarantine is a beneficial technique regardless of the origin of your fish. In large-scale breeding operations, illnesses and parasites like as ich, flukes, and fish TB are highly frequent.

Even in the highest quality breeding settings, some illnesses might arise, thus no new fish is guaranteed to be disease-free. Diseases are more prevalent in large breeding facilities and pet superstores, although they can occur everywhere.

Failure to quarantine new fish can lead to the introduction of difficult-to-treat illnesses into your aquarium. Some parasites and illnesses are annoying or repulsive, while others are lethal. If you choose not to quarantine your fish before adding them to your tank, you may compromise the health and well-being of your entire aquarium.

It may seem cumbersome to quarantine all new fish before introducing them to your tank, but it’s a far preferable alternative to having to treat an entire tank for disease and risking fish loss.

What if I Already Introduced New Fish Without Quarantining?

Don’t panic if you’ve already introduced additional fish to your aquarium without quarantining them! You still have alternatives for maintaining a healthy aquarium. Your first choice is to do nothing, particularly if the new fish have been in the tank for several weeks.

You might opt to closely monitor the aquarium and look for symptoms of disease in both new and old fish. This involves keeping an eye out for signs such as fin clamping, trouble breathing, fast breathing, sores, lethargy, white specks on the fins and scales, redness, jagged or torn fins, and a lack of appetite or difficulty feeding.

You may also treat your entire aquarium with broad-spectrum remedies to reduce dangers before symptoms appear. This involves the use of salt, antiparasitic drugs, antifungal medicines, and antibacterial therapies. Prophylactically treating your aquarium can prevent infectious illnesses from establishing a foothold and growing in your aquarium.

The earlier you address illnesses, the better, although not all diseases have apparent signs in the early stages.

What Items Will I Need for a Fish Quarantine?

Quarantine Tank

Your quarantine tank must be completely isolated from your main aquarium. A tank divider or breeding box will not fulfill quarantine needs. Prior to bringing fish home, this tank should have enough filtration and, if feasible, should be thoroughly cycled.

Tank Cleaning Equipment

Since the fish will be in quarantine for a minimum of two weeks, a quarantine tank must be equipped with water-change supplies. If the aquarium is not cycled, this is much more crucial. You need separate supplies for your quarantine tank so that you do not accidentally move water from your quarantine tank to your main aquarium.

Aquarium Salt

This may be placed straight to the quarantine tank or used to bathe your fish separately. It can be used to treat ich as well as other parasite disorders and infections. It is essential to understand that aquarium salt does not evaporate with water; therefore, if you continue to add salt without making water changes, you may end up with a high salt content that may be harmful to your fish.


You’ll need this to treat any external parasites your fish may have acquired during transport. Ideally, you should use this preventatively. Both Hikari PraziPro and Seachem ParaGuard are excellent options.

ParaGuard can also be used to treat fungal, bacterial, and viral infections on the skin’s surface. Seachem, which is powerful against internal parasites, will also be required. As well as Metroplex, 3% simple Epsom salt may be used to produce a medicinal food.


You won’t necessarily need something like this to use preventatively on new fish, but it’s a nice idea to keep on hand just in case disease symptoms appear. Seachem Kanaplex is an excellent alternative for a broad-spectrum antibiotic that is effective against both fungal and internal infections.

Water Test Kit

If you already have a functioning tank, you should have a trustworthy water testing kit. If you don’t already have one, you should get one that can measure pH, ammonia, nitrite, and nitrate levels. This is especially vital for a tank that has not been cycled.

Water Treatment Equipment

Any water added to the tank must be treated to eliminate chlorine and chloramines. It is prudent to maintain items on hand that can neutralize waste products such as ammonia. Seachem Prime neutralizes ammonia, nitrite, and nitrate, eliminates chlorine and chloramine, and promotes the health of the slime coat.

6 Steps to Properly Quarantine a Fish

1. Tank Setup

Ensure your aquarium is completely functional before introducing new fish. The filtration system should be operating correctly, and the water should be adequately aerated.

2. Observe Parameters

Check your water’s properties on a regular basis with the test kit. If your quarantine tank was not cycled prior to the introduction of new fish, you should monitor water parameters regularly and treat the water as necessary to eliminate or neutralize toxins.

If the tank has been fully cycled, you may monitor the water parameters every few days to confirm that everything is running well.

3. Treat External Parasites and Infectious Conditions

After your fish have acclimated to the quarantine tank for a day or two, treat them with an external anti-parasitic drug, such as PraziPro or ParaGuard. Follow all directions precisely and conduct any water changes that the product’s label suggests.

Be mindful that if the fish you’ve brought home are already sickly or frail, any therapies you provide may lead them to experience too much stress and die. This is a regrettable risk that must be taken to guarantee that the fish can be moved to the main tank.

4. Add Aquarium Salt

Do not begin adding aquarium salt until the preceding step has been finished. After completing the preceding treatment and doing any necessary water changes, aquarium salt can be added.

Aquarium salt is an effective therapy for ich and can prevent it from entering the main aquarium. However, aquarium salt is harmful to plants and invertebrates, thus it should only be used in a quarantine tank.

For tropical and delicate fish, use a 0.2% aquarium salt concentration, beginning with 0.1% on the first day and the remaining 0.1% on the second. For hardier fish, such as goldfish, use a 0.5% aquarium salt concentration with 0.1% added everyday for five days.

Salt must be dissolved in water before being added to the tank. Every time you make a water change, you must remember to replace any salt that may have been removed. Maintain your salt level for two weeks.

5. Treat for Internal Parasites and Infectious Diseases

Perform water changes over the course of several days to remove as much salt as possible from the aquarium’s water before beginning a pharmaceutical treatment.

Treatment for internal parasites and infectious illnesses is a recommended but optional phase in the quarantine procedure. Utilize an antibiotic that can treat bacterial, viral, fungal, and parasite illnesses.

6. Transport Your New Fish

After completing these processes, your fish can transfer into their new home. Quarantine should last at least two weeks, although it can easily last four weeks or longer. Avoid rushing the procedure. You want the quarantine period to be as safe as possible for your new fish, while also ensuring the safety of your existing fish.

In Conclusion

How to Properly Quarantine a New Fish” by BestForPets (bestforpets.org) has clarified that fish quarantining is a time-consuming operation that pays off in the end. Adding new fish to your aquarium can be stressful for you, the new fish, and your existing fish.

Quarantining helps ensure that everyone remains healthy. It is fairly typical for pet retailers or breeders to sell fish with parasites or diseases.

Occasionally, signs of a disease may not manifest until several days or weeks have passed. Quarantine allows for the observation of these indications and symptoms, as well as preventative treatment before diseases manifest.


Author Image

Dr. Deborah Fletcher

Deborah R. Fletcher, DVM, is a skilled veterinarian with more than 15 years of experience dealing with companion and exotic animals. She has experience caring for a variety of animals, including household cats and dogs, reptiles, birds of prey, and even primates. Dr. Fletcher is a valuable part of the BestForPets team, where she contributes to their aim of providing pets and their owners with the finest possible treatment and services.

Veterinarian (DVM) Dr. Deborah Fletcher


Rated 0 out of 5
0 out of 5 stars (based on 0 reviews)
Very good0%

There are no reviews yet. Be the first one to write one.

Related articles