How to Quarantine Fish the Easy Way

Many beginners may not know this, but one of the easiest ways to stop your fish from getting sick is to set up a quarantine tank. This separate aquarium is used to temporarily hold newly purchased fish or ailing animals that need a quiet environment to heal. You can monitor their health and provide treatment if necessary. Once they are fully healthy and free from disease, you can add them safely to your main aquarium without infecting any existing fish.

Materials for the Hospital Tank

– Clear plastic tub or aquarium with a lid – Aquarium filter with low flow, like a sponge filter – Aquarium heater and thermometer Aquarium decorations and hides Water conditioner – Trio of quarantine medications (includes Mardel Maracyn, Aquarium Solutions Ich-X, and Fritz ParaCleanse)

How to Set Up a Quarantine Fish Tank

1. You should keep your quarantine tank out of direct contact with your main display tanks to prevent cross contamination. (Other best practices include using a separate set of nets and siphons for the quarantine setup and washing your hands after each time you touch the quarantine fish tank.) 2. For plastic tubs, drill holes in the lid to allow airflow and cut a small rectangle at the sides for power cables or airline tubing to pass through. You can also mark the tub side with 1-gallon measurement line lines, which will make it easier for water changes and medication dosing.

For a low cost quarantine setup, you can use a transparent plastic container. You can drill holes in the lid for better airflow and equipment installation.

1. Water conditioner: Fill the hospital tank with enough water. 2. You can add fish tank ornaments and a heater to your aquarium. A bare bottom aquarium setup is ideal for cleaning the hospital tank, as well as inspecting the fish’s waste.

A bare tank should be adorned with aquarium decorations. This will provide enough cover. The extra shelters will help sick fish hide better.

1. Add the fish and observe their behavior. If necessary, administer medication. Before you add medicines, make sure to remove any chemical filters (such as activated charcoal) and UV sterilizers. 1. If your fish is already sick, and you are able to identify the disease, give them the appropriate medication and follow the instructions on their packaging. This article will help you determine if your fish have the disease. 2. Fish purchased from a local fish market or breeder that you trust will be healthy, you should feed and monitor the fish for at least two days. You can see Step 5a above to identify an illness. ParaCleanse may be recommended to prevent you from becoming ill. 3. You should treat any fish purchased from an untested source such as an online retailer or pet store chain. These medicines are safe for scaleless fish, shrimp, fry, snails and live plants. They also contain antifungal and anti-parasitic active components. One packet of ParaCleanse, one packet of Maracyn and one teaspoon (5 mls) of IchX should be taken for every 10 gallons. Let the medication sit in the water for 7 day without feeding the fish.

Description: Quarantine medication trio

1. After treatment is completed, do regular water changes each week to gradually remove the medications over time. Fish can be helped to strengthen their immune systems with high quality fish food such as frozen foods. 2. We recommend quarantining most new fish for 4-6 weeks since the last disease symptom or death was seen. For extra safety, you can add two healthy fish from your main tank to the fish-hospital tank to see if they become sick. If all is well, then you can release the individual fish from quarantine. 3. After quarantine is completed, you can clean and dry the hospital tank. If you are planning to buy more fish, leave everything running until the next batch.

Most Common Questions about Fish Quarantine

How big does a quarantine tank need to be?

Because it is temporary, the quarantine tank doesn’t need to be larger than the recommended size for permanent housing. A hospital tank with less water volume also allows you to use less medication when treating the fish.

Keep a quarantine tank running smoothly. Use a spare sponge filter, or additional filter media in a hang on-back filter to clean one of your display tanks. Whenever you need to quarantine some fish, move that extra sponge filter or filter media to the hospital tank so it will bring over lots of beneficial bacteria to help purify the water. After the quarantine period is complete, put the sponge filter or filter media back in your main tank. Our full article explains what cycling is and how to cycle your aquarium.

Add a sponge filter to an already-established tank. Then, use the extra filter media to introduce beneficial bacteria to the hospital tank.

Can I quarantine fish inside a bucket? Yes. Any clean, food-safe container large enough can be used in an emergency. We recommend that you use a container with clear sides to allow you to view the fish from all angles and see if they are improving or getting worse.

Should you quarantine shrimp and snails? Dwarf shrimp can sometimes carry diseases, especially if purchased directly from importers, so if you are bringing in a batch to add to an existing colony, consider putting them in quarantine first to observe their condition. We have found that snails are rarely infected so we don’t bother with quarantine. Instead, we add them to our aquariums.

Do I have to quarantine my first fish? If you are setting up your first tank, you can theoretically add new fish directly into the aquarium without setting up a separate quarantine tank since there are no existing animals to protect. A separate hospital fish tank might be necessary if the aquarium is too large or the fish are not small enough to fit in a standard quarantine. Dosing medications in smaller volumes of water is cheaper than purchasing an entire aquarium.

If your main aquarium contains live plants and snails, this is another example. Aquarium salt is often used as an additional defense in cases where the quarantine medication trio fails to work. Snails and plants don’t like high salt concentrations so it is best to move your fish into another container.

How can I treat fish with aquarium salt? Aquarium salt is a widely-available and inexpensive “medicine” that is effective in treating bacteria, fungus and other parasites. It is not suitable for aquatic plants, snails and certain fish like anchor catsfish. See our aquarium salt article to learn more.