Quarantine your fish... Why it is important?


A must-have step to treat your newly purchased fish if you don’t want to regret.


Never heard of it as a must-have step when you have cats or dogs as pet, huh? Now, you will if you pursue fishkeeping hobby. A lively aquarium with groups of healthy, beautiful fish occasionally splash around costs you more than just purchasing and simply put them in your aquarium at once with other fish. Sound bewildered huh, don’t worry in this article we will share with you our useful tips we frequently apply when performing quarantine.

Photo by Huy Phan on Unsplash


Quarantine means you isolate your fish from others in a separate tank to closely observe and examine its conditions. You do the quarantine when you spot your fish’s illness or when you’ve just purchased new fish. Now, at this point, one may wonder why I should do the quarantine for the latter. It’s easy to answer huh? You do the quarantine for your ailing fish and what make you think your newly purchased fish does not carry any illness? I know what you may say next. You may be overwhelmed and say you will return your fish to the seller and never buy any fish at that store again. Of course, I’d do that if I were you but the thing is before you recognize your newly purchased fish’s illness, you must have kept it in your main aquarium together with your other fish. That said, even if you return the new fish, you’ve potentially spread diseases to your current fish. Yep, worse scenario now because it will take you quite much time and effort to handle this mess.

That’s why we told you quarantine is so important. It’s not difficult to prepare and carry out the process. Just simply follow our instructions below and you’ll find a little effort at the beginning can save so much trouble later.

At Splashy Fish, we guarantee that all fish will go through the quarantine process for a period of 14-day before sale. We believe you would like to make new interesting “friend” but we are more than 100-percent sure that you will be much happy if your friend is not only interesting but thriving, lively and sustainable as well. That’s why we care about the quality and strive to provide you the best we can. Visit our store to find what surprise is waiting for you.

What do we need?

Instead of putting your new fish in the main aquarium, you keep it in a separate tank and make sure that tank shares similar conditions to your main aquarium. We will show you what is needed first:

  • Quarantine fish tank
  • Since it is a temporary tank for quarantine purpose, just make it easy by using a clear fish tank or clear plastic container with a lid. 

    Advice: Of course, we prefer a clear fish tank because it is specialized equipment for keeping fish. In addition, you can re-use it for multiple times whenever quarantine process is needed. It is worth investing for a long-term use purpose.

    If you use a clear plastic container with a lid, drill some holes on the lid to let the air flow through, also cut a small rectangle on the side for power cables and airline tubing set up.

    Your tank/ container should be bare bottom one so it allows you to clean the tank easily and examine fish’s waste when needed.

    The size of the quarantine fish tank or container is subject to the size and the number of your fish. Normally, it does not need to be as big as your main aquarium. Moreover, the less the water volume contained in your quarantine tank/ container, the less the medication needed to treat your fish.

  • Aquarium filter
  • It should generate low flow because you are treating ailing or potential ailing fish, strong flow may be too much for them.

  • Aquarium heater and thermometer
  • Aquarium decorations
  • Yes, they are needed, especially those providing hiding places. Your fish may not be in a good condition, it is usually for them to seek a hide. By putting some decorations serving this purpose in the tank, your fish may feel more comfortable. Consider using plastic decorations since you can easily sanitize and disinfect the decorations after quarantine.

    Substrate and gravel may not be necessary because they make it harder for you to follow up and examine the water conditions and fish’s waste. 

  • Water conditioner
  •       This is for detoxifying chlorine/ chloramine in the tap water. We highly recommend to use Seachem Prime
  • Quarantine medication trio We highly recommended API E.M. ERYTHROMYCIN, Kordon Rid-Ich Plus, API GENERAL CURE OR FRITZ PARACLEANSEFRITZ MARDEL MARACYN® TWO

    Big note: Hygiene is important. Carefully wash your hands with soap after exposure to the quarantine fish tank. Also, use a separate set of equipment (e.g., nets, siphons, buckets, etc.) for your quarantine fish tank. Or else, cross contamination may occur and all what you’ve done so far shall be useless.


    Let’s start the process …

    Step 1: Fill your quarantine fish tank with water and add water condition.

    Step 2: Then, install the aquarium heater and filter and decorations. Keep the water temperature constantly at 85F (~ 29.4C).

    Before you take Step 3, remind what we’ve shared with you about fish tank cycle. Your quarantine fish tank must be cycled, too. Forget that or don’t know what fish tank cycle is and how to do, you can find all about it here.

    Step3: After that, add your fish and watch their physical appearance and behavior. 

    Step 4: Now, the important part comes. Before you start treating your fish with medicines, remove any chemical filtration (like activated carbon) and UV sterilizers.

    You may find 3 most scenarios about your fish: 

    1. Spot the illness at once. Treat your fish with medication curing that illness, follow the manufacturer’s instructions on the package.
    2. Unable to detect any symptoms by bare eyes after watching for a couple of days, you now think your fish has no problem at all. Well, you may have your conclusion, but we still insist you proactively treat them with API GENERAL CURE (as per the manufacturer’s instructions) before you release them to your main aquarium with other fish. An extra treatment to ensure any remaining internal parasites which are harder to spot will be completely cleared out does no harm.
    3. Uncertain about your fish’s conditions. This normally happens when you purchase new fish from an untested source. If it the case, use the quarantine medication trio, including API E.M. ERYTHROMYCIN, Kordon Rid-Ich Plus, API GENERAL CURE




    Kordon Rid-Ich Plus


    Active Ingredients


    Fomaldehyde, methanol, malachite green chloride

    Metronidazole and praziquantel

    Treatment for

    Bacteria infections

    Fungal infections and external parasites

    Internal and external parasites

    Common Diseases

    Fin rot, popeye, gill disease, open wounds

    Cottony growths, ich (white spot disease)

    Tapeworms, flukes, wasting disease


    The medication trio contains a blend of antibiotic, antifungal, and anti-parasitic active ingredients that are safe for scaleless fish, fry, shrimp, snails, live plants, and beneficial bacteria. Dose 1 packet of API E.M. ERYTHROMYCIN, 1 packet of API GENERAL CURE, and 1 teaspoon/cap (5 ml) of Kordon Rid-Ich Plus for every 10 gallons of water. Let your fish soak for 7 days without feeding the fish.

    After 7-day period, do regular water changes each week to gradually remove the medications. Also, feed them high quality food to help them build their immune systems.

    The ideal quarantine period is around 4 to 6 weeks. After that time and no symptoms have been found in your fish, you can let them join your main aquarium.

    Step 5: Like we said above, after you finish, clean your quarantine fish tank and other related equipment so they can be re-used for the next quarantine.


    Other info we think you may know:

    • If you are a starter and purchase first fish batch, you may not need to set up a separate quarantine tank since your main aquarium is that quarantine tank, too. Just do the quarantine in your main aquarium. However, if your aquarium is way much larger and your fish are small, you may consider a separate tank for cost-saving as we once mentioned the less the water volume contained in your quarantine tank/ container, the less the medication needed to treat your fish.
    • If you buy shrimp instead of fish, we still suggest you process the quarantine. Shrimp sometimes carry disease, particularly when you purchase directly from importers. Contrary to shrimp, snails rarely carry illness, so you may consider skipping the quarantine step.


    Last, after reading all of it, understanding its importance but finding it too complicated to perform or no time to do so many steps, you may consider an alternative, buy new fish at a pet store which already carried out the quarantine process.