Quarantine tank setup

Quarantine Tank Setup

A quarantine tank setup is a crucial part of owning and maintaining a saltwater aquarium. You’ll ensure the safety of every fish and invertebrate you add to a tank. Not to mention you’ll save yourself hefty medication bills down the road. But how do go about making sure your quarantine zone doesn’t turn into an incubation tank for disease? And why is this step so critical? Not to worry – you’re going to get a crash course on everything you ever wanted to know (and possibly things you didn’t!).

Table of Contents: Quarantine Tank Setup

The Purpose of a Quarantine Tank

When you finish your quarantine tank setup, you accomplish multiple functions. That separate tank is:

  • A physical barrier between new saltwater fish and the display tank, preventing contamination from occurring.
  • The easiest way for you to closely observe and monitor the behavior of the new saltwater fish out in the open. Most newly introduced saltwater fish hide in live rock or other structures in your aquarium and only come out once they reach a minimum comfort level. And that varies with species and individual.
  • A way for you to safely treat and remove any health threats without harming any of your other livestock.
  • The “recovery place” for your newly purchased saltwater aquarium fish to eat, gain strength, and recover from the stresses of shipping and display at the local fish store. Not to mention getting them ready to compete for food and shelter with the fish in your reef tank.

Why Quarantine Your Fish?

Saltwater fish in the aquarium hobby are prone to injury, disease, infection, and parasites. The collection and transportation from the aquaculture facility or reef often cause damage and stress. The closed systems the fish are kept in are ideal for harboring and transmitting diseases while lacking the natural counter-measures which keep infestations in check in natural habitats.

Just ONE infected fish can quickly spread disease or parasites throughout a tank. The cascade of events then leads to devastating consequences. Once your display tank gets infested, it can be a nightmare to get clean and free of parasites again.

Have you heard the expression “an ounce of prevention is worth a pound of cure?” In the saltwater aquarium hobby, an ounce of prevention is worth a KILOGRAM of cure. This is because a kilogram is 2.2 times heavier than a pound. (And that’s how serious you need to take preventing parasites and disease entering your aquarium)

What About Other Tank Life?

Incidentally, fish aren’t the only lifeforms you want to “cycle” through your quarantine tank. ANYTHING carries the potential to bring in parasites or bacteria. So you’ll want to make sure your invertebrates, live rock, and plants spend time inside the quarantine, too. Otherwise, you’ll go through all of your work with your fish only to expose them to possible problems in your display tank from other sources. And live rock? It can bring PLENTY of hitchhikers along! Some you may not mind, but others can wreak havoc on your tank. (Aiptasia, anyone?)

So make sure that any new creature you bring home (or anything that might HOUSE a creature) gets a “time out.” (You’re not going through this quarantine tank setup for nothing, after all!)

Quarantine tanks work for all additions to saltwater aquariums

Quarantine Tank Setup Equipment

You don’t need a lot of fancy gear for a quarantine tank setup. The basic premise of a quarantine tank is a small, no-frills tank, using separate equipment and water from your display tank. So you don’t need a bunch of fancy equipment:

  • 10 or 20-gallon (38-76L) tank, complete with a lid and light
  • Sponge filter (or other inexpensive, easy to set up filter, including hang-on-back style)
  • Air pump and airline
  • Aquarium heater
  • PVC Pipe
  • Timer
  • Surge protector/power strip
  • Preferred brand of aquarium salt

I easily tracked down a sponge filter, heater, air pump, and airline for a few bucks on Amazon. You can also watch for sales at your local fish store. Stores in my area periodically run a dollar-per-gallon sale every now and then. That’s a great time to pick up a spare tank for a low, low price.

Quarantine Tank Setup: Step-By-Step

Once you have your supplies gathered, you’re ready to get started on your quarantine tank setup. We’ll walk through every step, one at a time. Remember, you’re creating a healthy environment for your new aquarium additions. So you want to take as much care with this process as you did with your display tank. Even if you don’t plan to show off your quarantine work, you want your fish to feel safe and comfortable inside. More importantly, you need to e able to pick up potential health problems ASAP.

So roll up your sleeves, and let’s get to work on that quarantine tank setup!

Step 1: Preparing the Quarantine Tank

So I missed one crucial piece of equipment you’ll need for your quarantine tank setup; you’ll also need a sponge. I prefer Scotch-Brite and Magic Eraser brands, but you can use whatever sponge you have available. You just want to make sure it’s brand new, with no soap or chemicals embedded in the sponge.

Quarantine tank setup starts with cleaning the tank

The first step in quarantine tank setup is to clean it out. You DON’T want to use harsh chemicals – or ANY chemicals unless you absolutely have to. Soak the tank for several minutes in clean freshwater to soften any hard mineral deposits. Then scrub it clean with your sponge. I prefer to clean my tanks outside (weather permitting) so I can splash around a bit and use the hose to fill the tank quickly.

If you have hard mineral deposits on the glass that won’t come out with a simple scrubbing, try using a razor blade (ONLY if the tank walls are made from glass, NOT acrylic). The hard deposits should scrape off. 

If you previously had an infected fish in the tank, consider disinfecting the tank using hyposalinity. Hyposalinity is a fancy term for a solution with a low concentration of salt. The best low salt solution is (you guessed it) freshwater. Saltwater parasites generally don’t survive in freshwater, so run your tank for a few days with fresh water (after scrubbing it out – a good cleaning is needed to battle any kind of infection or infestation).

Step 2: Quarantine Tank Setup

The quarantine tank setup is fairly straightforward. It is best to find an out-of-the-way location where your fish can gradually get used to living in your home.

  1. Place the tank on its stand.
  2. Fill it with saltwater.
  3. Place the heater in the tank, and set the temperature (if needed) to 78F/25.5C. Plug the heater into the power strip.
  4. Connect the sponge filter to the airline and submerge the filter in the water.
    1. Squeeze the sponge to remove any bubbles and prevent it from floating up.
  5. Connect the airline to the air pump and plug it into the power strip.
  6. Place a few short lengths of PVC pipe in the tank to give the fish somewhere to hide.
  7. Put the lid on top.
  8. Plug lights into a timer and then connect the timer to your power strip.
  9. Go grab a snack and congratulate yourself on a job well done with your quarantine tank setup.

Supplies for setting up a quarantine tank

Step 3: Cycling Your Quarantine Tank

Just because you filled your quarantine tank with salt water doesn’t mean it’s ready for fish. When fish are kept in an aquarium, they release waste products containing ammonia into the water. Ammonia is toxic and can burn or kill fish when they reach high enough levels. Sometimes, this mysterious death is called new tank syndrome. To avoid new tank syndrome, you must cycle the aquarium before you can add those first fish. Be sure to cycle your tank and confirm the biological filtration is working properly before adding your first fish.

Selecting the best beginner fish for your saltwater aquarium is an important decision. If you’re just starting out, I recommend you avoid these fish.

Step 4: Adding Fish to the Quarantine Tank

Once your quarantine tank finishes cycling and you pick out the perfect fish for your aquarium, it’s best to acclimate the fish to your aquarium water before dropping them into the tank. Place the new fish in a bucket or small plastic container and use a drip acclimator to drip water from the quarantine tank into the bucket. Once you drip enough water (double or triple the original volume of water) gently scoop your new fish out of the bucket and transfer them quarantine using a specimen container (or similar plastic container).

Try not to add too many fish to the quarantine tank at the same time! This can compromise all of your careful quarantine tank setup work – not to mention leading to stress for the new additions. You don’t want to cope with either problem if you can help it.

Step 5: Monitoring Fish in Quarantine

You want to monitor the fish in your quarantine tank for at least 30 days. Thirty days is the BARE minimum and even then it’s a bit risky. Since parasites like saltwater ich have a lifecycle of about 28 days (depending on the temperature and a few other variables), you have a reasonable assurance that the coast is clear if you monitor your fish in quarantine for those 30 days and observe no parasites or suspicious behaviors such as shimmering, scratching, etc.

But if you have patience, you can (and should) wait even longer.

Frequent water testing is an important part of quarantine tank setup

While monitoring your fish in quarantine, you also want to test the water for ammonia, nitrites, and nitrates. If your tank is properly cycled and the biological filter is working as it should, you should detect NO ammonia or nitrites. If you test and discover ammonia, take immediate action and do a partial water change to lower the toxic concentration.

You should also pay close attention to the behavior and condition of your fish to make sure they aren’t exhibiting stress from the higher levels. If you know you have species that are delicate (and need pristine water conditions), single them out for particular observation.

Periodically check the pH, temperature, and specific gravity to make sure the important reef aquarium water parameters are stable and normal in your tank.

You also need to monitor all of your water parameters

Feed your fish small meals a few times each day. And take the time to watch the feeding closely to ensure your fish are active, healthy, and eating properly. Immediately clean up any uneaten food.

Visually inspect and observe the fish for parasites, cuts, scrapes, and any signs of injury or infection. If you see any damage or parasites, do further research to investigate the recommended treatment options (you’ll find everything from hyposalinity to antibiotics). Take the appropriate action.

Please note that if you DO detect a parasitic infestation (like saltwater ich) you have to start the calendar count-down of your quarantine period over AFTER you rid your tank of the pest.

Careful Quarantine Observations

If you are going to properly use a quarantine tank setup, you have to be sure you maintain your livestock in quarantine for the full amount of time. And that means you need to be absolutely positive the fish showed no symptoms during that time. The best method to help with this is to write down your observations daily in a journal.

If you don’t record your observations, you run the risk of missing a day, forgetting what you saw, or even convincing yourself that you don’t have to wait for the full period. (After all, 30 days is a long time, and you can convince yourself you don’t need to wait that long)  Any number of things can end up invalidating the quarantine you did and put your entire display tank at risk.

Keep your recorded quarantine tank journal entries so you can learn and keep track of your progress.

For More Information

A quarantine tank setup can feel overwhelming when you first start out. Luckily, this handy YouTube video is available to walk you through the process (and make you laugh at the same time):

How to setup a fish quarantine tank!

Say you forgot the quarantine step, or you noticed a problem during those 30 days. If it’s already too late and your fish are actively infected with a parasite (like saltwater ich – notice a theme?) you need to focus on treating saltwater ich. 

Or maybe you want to know what to do when you are finished with quarantine.

Finally, you may be getting started with everything and want to learn more about setting up a saltwater aquarium.

Written by Albert B. Ulrich III, Author of The Reef Aquarium Series of books: The New Saltwater Aquarium Guide, How to Frag Corals, 107 Tips for the Marine Reef Aquarium, and Reef Journal.





8 responses to “Quarantine Tank Setup”

  1. Alan

    I’m confused. It can take a month or so to cycle the quarantine tank. When you finally introduce the quarantined fish to your display tank how do you keep the Q tank cycled if you’re not quarantining a new fish for a while? It doesn’t seem practical to have to cycle a tank every time you want to introduce a new fish.

    Am I missing something?

    1. Alan, thanks for the question, and apologies for the confusion from the article above. You would either leave the QT running, or if you shut it down (and you have your reef tank running) you can seed the QT with bacteria from the reef tank (via a sponge in your sump, for example). If you have a ‘mature’ sponge from a fully cycled and healthy reef tank, that’s likely sufficient to jumpstart your QT again with a single fish.

  2. Shanmuga Sunthar

    My questions are similar to Alan’s:
    – How long should I cycle the QT?
    – How will I know that the QT is cycled and ready for use?
    – As we don’t buy/add new fish all the time.. should we run QT all the time or run when needed only?
    – Should I shutdown the QT when not used?
    – Can/should I use the same QT for other creatures e.g. shrimps, snails, corals, etc.

    1. Hi Shan, thanks for the great questions and additions to Alan’s. The time for cycling may vary a bit–the way you know it is done and ready is that you detect ammonia in the beginning…because you introduce ammonia into the tank on purpose to start the nitrogen cycle…and then…after about 10 days or so you no longer detect ammonia or nitrite, only nitrate. Then you know the tank has ‘cycled’, meaning you have enough bacteria there to convert all detectable ammonia and nitrites into nitrate.

      You don’t need to keep the tank running all the time. What I do is put a sponge from a sponge filter in the sump of my display reef tank, then when I need to start up my QT again, I take that sponge out and use it to jump start the QT cycle. As you can see, there is some hassle factor with shutting down or starting back up, so I typically leave it running unless I know I don’t plan to add anything new for some time.

      I don’t recommend using the same QT for invertebrates, including corals. The reason for QT is to isolate and potentially treat parasitic infections (most are also invertebrates) and those treatments kill invertebrates, so you don’t want them mixed and you don’t want to risk ‘last month’s’ treatment still lingering in the tank leeching back into the water, etc., Hope that helps

  3. Shanmuga Sunthar

    Hi Al,

    Thank you very much for the clarifications.

    Have 2 more questions if you don’t mind:
    1. What are the ways/methods to move fishes safely to DT after the quarantine period, as the are still high risk of introducing dangerous contaminants from the QT in the process?
    2. Would like to know how to setup and quarantine other inverts e.g. corals, snails, shrimps, etc.


    1. Hi Shan, thanks for the great questions. To move the fish to the DT, you just scoop them out using a plastic specimen container (I like to ‘chase’ them with a net so they swim into the container on their own). Since the QT tank typically does not have a lot of decorations and no rock, it is usually pretty easy. Then do a drip acclimation to equalize water parameters, scoop them out (same container) and put them in.

      Regarding the other QT, the principles are the same as the ‘fish’ QT. The tank can afford to be a lot smaller, probably. With corals you would want to have reef-quality light. You can use the same tank for inverts and corals. While my next sentence is not the best advice, I do believe it to be true:

      I don’t think a lot of us (myself included) QT our clean-up crews. The reality is that they certainly have their own parasites and diseases, but clean-up crews are generally inexpensive and their problems aren’t as well known to proliferate in the tank. A close visual inspection is probably what most people give, looking for obvious hitchhikers like pyramid snails or something like that.

      Corals, on the other hand, there are two potential precaution steps: the first is a coral dip…you can research that topic…essentially you use parasite killers to clean off frags before putting them in your tank. Then you keep them in QT for a shorter period of time just for observation to be sure you don’t have parasites or aiptasia before acclimating them to your DT. With corals, you’re not necessarily isolating long enough for a parasite cycle to pass, but more observing and inspecting to confirm no parasites are visible and no issues like brown jelly disease or necrosis that could be passed in your tank.

      I recognize this is a lot of work and ‘extra’ tanks. You will find that many people make trade-offs and decide for themselves what they are willing to risk vs. do to keep things clean and tidy.

      Hope that helps.

  4. Hey Al, Thanks again for all of the great info. I am a research junkie, so this blog really helps with a LOT of info in one place.
    I know there a lot of variables that go in to the answer so here goes…
    Realistically, how often can one expect to have to treat a new animal in quarantine, assuming it’s a new purchase vs. a sick animal pulled from the DT for treatment and assuming you have a reputable LFS that treats their stock well.

    1. Hi Alex,

      That’s a great question and I really like how you framed it. How many times do we have to quarantine to prevent 1 episode of infection? Unfortunately, that’s also a really hard question to answer. It would be a fantastic study and subsequent publication. What I can tell you is that before I started quarantining my fish, I had 2 separate, unrelated, devastating ‘tank crashes’, within a few years, that were caused by saltwater ich that eventually spread and killed all the fish. While I don’t have great records going that far back, we can estimate what the risk may have been.

      If we assume only 1 was ‘patient zero’ that spread it, probably 1 in 15 or 1 in 20, happening twice, separately, years apart. I can also share one other stat within my last several purchases, where I have better records, there were 2 sick fish out of 8 that I treated in quarantine for issues before moving to their permanent location.

      Of course, the risk here is in generalizing this small sample size out to a massively large population. I know of others who are proud to share they’ve never had a problem. Since I have personally experienced devastating losses, and since those losses can occur because of a parasite introduced by any one fish at any time, I recommend always quarantining first. As we’ve demonstrated here with this answer, you are almost guaranteed to quarantine otherwise healthy fish, but you protect the animals in your tank that you’ve worked so hard to care for.

      Hope that helps. I know I certainly evangelize a specific point of view here rather than take an agnostic risk vs. reward approach. But I still have the scars from my first two episodes. I have also heard from countless readers here who have given away their tanks and quit the hobby after similar experiences. Rather than see that much loss of life, and interest in this amazing hobby, I therefore advocate that we all quarantine our fish, always.

Leave a Reply

Your email address will not be published. Required fields are marked *