quarantine tank setup

Quarantine tank setup

This post explains the need for a quarantine tank setup and provides a checklist to help you get started.

Why quarantine your fish?

quarantine tank setup

Saltwater fish, in the aquarium hobby, are prone to injury, disease, infection and parasites. The collection and transportation from the aquaculture facility or reef can cause damage and stress. The closed systems we keep the fish in are ideal for harboring and transmitting disease, while lacking, at the same time, in the natural counter-measures which keeps infestations in check in the ocean.

One infected fish can quickly spread disease or parasites throughout your tank and can cause a cascade of events that leads to devastating consequences. Once your display tank is infested, it can be a nightmare to get clean. You may have heard the expression: “an ounce of prevention is worth a pound of cure,” but in the saltwater aquarium hobby, an ounce of prevention is worth a kilogram of cure…which is 2.2x’s heavier than a pound.

What does a quarantine tank do?

The quarantine tank, once  set up, serves multiple functions. It provides a:

  • Physical barrier between your new fish and the display tank, preventing contamination in the first place
  • Way for you to closely observe and monitor the behavior of the new saltwater fish out in the open (most newly introduced saltwater fish will hide in the rockwork or other ‘structure’ in your aquarium and only come out once they reach a minimum comfort level—which varies by species and individual)
  • Way for you to safely treat and remove any threats without the risk of harming any of your other livestock
  • ‘Recovery place’ for your newly purchased saltwater fish to eat, gain strength, and recover from the stresses of shipping and display at the local fish store—and get ready to compete for food and shelter with the other saltwater fish in your reef tank.

Quarantine tank equipment checklist

You don’t need a lot of fancy gear to set up a quarantine tank. The basic premise of a quarantine tank is that you want to set up a small, no-frills tank that has separate equipment and water from your display tank. Here is all the equipment you need:

  • 10 or 20 gallon tank with a lid and light
  • Sponge filter
  • Air pump and airline
  • Heater
  • PVC Pipe
  • Timer
  • Surge protector/power strip
  • Preferred brand of aquarium salt (unsure which brand to choose? read more here)

I picked up a sponge filter and heater, air pump and airline for just a few bucks on Amazon. Watch for sales at your local fish store. Stores around me periodically run a dollar-per-gallon sale every now and then, which is a great time to pick up a spare tank for a low, low price.

Step 1: Preparing the quarantine tank


In addition to the equipment listed above, you will also need a sponge (I prefer scotch brite and magic eraser brands), but you can use whatever sponge you have available–as long as it is brand new as well as soap and chemical free.Untitled-11

The first step in preparing your new quarantine tank is to clean it out. You don’t want to use harsh chemicals–or any chemicals at all, if you don’t absolutely have to. Soak the tank for several minutes in clean freshwater to soften up any hard mineral deposits and 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, you can use a razor blade (if the tank walls are made from glass NOT acrylic). The hard deposits should scrub right out. 

If you previously had an infected fish in the tank, consider disinfecting the tank with hyposalinity. Hyposalinity is a fancy term for a solution with a low concentration of salt. The best low salt solution is…you guessed it…fresh water.

Saltwater parasites generally don’t survive in freshwater, so run your tank for a few days with freshwater (after scrubbing it out).

Step 2: Setting up a quarantine tank

Setting up a quarantine tank is fairly straightforward. It is best to find an out-of-the-way location where your fish can gradually get used to life in your home. Go here for more information about selecting the best location.

  1. Place the tank on the stand
  2. Fill it with saltwater
  3. Place the heater in the tank, set the temperature (if needed) to 78 degrees F and 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 get out any bubbles and to help keep 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 some place to hide
  7. Put on the lid
  8. Plug lights into a timer and plug the timer into your power strip
  9. Go grab a snack


Step 3: Cycling

Just because you filled your quarantine tank with saltwater doesn’t mean it is ready for your first saltwater fish. When fish are kept in an aquarium, they release a waste product called ammonia into the water. Ammonia is toxic and can burn or kill the fish. Sometimes, this mysterious death is called new tank syndrome. To avoid new tank syndrome, you must cycle the aquarium before it is ready for your 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. You can learn more about that here. When you are just starting out, I recommend you avoid these fish.

Step 4: Adding first fish

Once your quarantine tank has completed cycling and you have picked out the perfect fish for your aquarium, it is best to acclimate the fish to your aquarium water, before dropping them right in 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 have dripped enough water in to double or triple the original volume of water, gently scoop your new fish out of the bucket and into quarantine using a specimen container (or similar plastic container). It is also important not to add too many fish into the  quarantine tank at the same time. 

Step 5: Monitoring your fish in quarantine

You want to monitor the fish in your quarantine tank for at least 30 days. 30 days is really the bare minimum and is still a little bit risky. If you have patience, you can wait even Untitled-9longer, but since parasites like saltwater ich have a lifecycle of about 28 days (depending on the temperature and a few other variables), you can have a reasonable assurance that the coast is clear if you monitor your fish in quarantine for a full 30 days and observe no parasites, or infected behaviors like shimmering, scratching, etc.

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

Untitled-8Periodically check the pH, temperature and specific gravity, to make sure the important reef aquarium water parameters are stable and normal in your tank.

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

Visually inspect and observe the fish to look for parasites, cuts, scrapes and any signs of injury or infection. If you see any damage or parasites, do some further research to investigate the recommended treatment option, like hyposalinity or antibiotics and 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 over once you have rid your tank of the pest.

Record your 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 are absolutely positive that the fish has had no symptoms during that time. The best method I have found 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, convincing yourself that you don’t have to wait the full period (after all, 21 days is a long time…you would say to your future self) or any number of things which could end up invalidating the quarantine you did and could 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

If it’s already too late and you fish are actively infected with a parasite, like saltwater ich, check out this article about how to treat saltwater ich. 

Or if you want to learn more about how to set up a saltwater aquarium, check out this article.

Watch this video about setting up a quarantine tank:


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.

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  1. Hi Albert,
    Thank you for writing about this important subject. Also, …. thank you for letting us reply!
    I was going to do salt water but changed “midstream” to freshwater. While I prefer the saltwater fish I am sure the freshwater tank will be easier to maintain and a modestly planted tank with some driftwood and rock decor will be relaxing and easy to look at.
    Anyway, my question is regarding a freshwater quarantine tank. What, in your opinion, is the best way to cleanse a FW tank after I treat (for example), some fish with a parasite problem ? In this case, obviously hyposaline H2O will not do the trick. But somehow I have to sanitize the quarantine tank. What are your thoughts about this?
    I am very curious about your thoughts on these matters. Thanks in advance.
    Best wishes and best fishes to you, Bob

    1. Author

      Bob, thanks for the comment and questions. I started out with a freshwater aquarium years ago and miss it sometimes–so in a way I’m reminiscing a bit because of the premise of your question. A lot of the freshwater medications simply call for large water changes (if I recall properly). If you medicated at the right dose, the problem should hopefully be eradicated, so you don’t have much of a clean-up or clean-out problem.

      However, I am inclined to recommend using a similar (but perhaps reverse) approach with freshwater. In the same way that hyposalinity would rupture saltwater parasites, I believe saltwater to be equally problematic to freshwater parasites. I would not want chemicals or any type of cleaning agent, I would raise the salinity quickly (assuming the tank is void of livestock), keep it there for a few days, dry the tank thoroughly for a few days (killing anything water born) and then do a very thorough towel cleaning. But that’s somewhat hypothetical because I haven’t done it for years, but I do believe the hyper salinity (in this case) and dry spells for the tank should be more than enough to keep waterborne risk to a bare minimum. As far as your sponge filter starter, I haven’t used that brand but it technically makes sense.

      What type of freshwater fish are you thinking about?

      1. Thanks Albert, that answer was terrific. Why didn’t I think of that simple elegant solution? I could hyper saline the tank for a few days (without livestock). Then let dry completely and prep for the next quarantine procedure.

        Have a good day. Regards, Bob

  2. Amen to quarantine. Around 1971 I had a magnificent 55 gal. display tank. I had a juvenile Coris gaimard, Coris aygula and dragon wrasse, and a Labroides cleaner wrasse,.There were 4 small angels, an Emperor, a Bicolor, a Coral Beauty and a Rock Beauty. There were also a purple dottyback, a zebra sailfin tang and did I mention my Moorish Idol? Moorish idols don’t eat? This one never got the memo. I had a 20 gal. isolation tank; new fish were kept there for 3 weeks before they went into the community tank and all was well. I bought a Regal angel, which I thought might not survive 3 weeks in the 20 gal.,so I did one of the dumbest things I’ve ever done in my life. I took a chance, put him straight into the 55 gal. and guess what? He had the saltwater ich-WIPEOUT! It broke my heart.

    1. Author

      David, thank you for sharing that experience. I’m sorry for those losses. That is devastating. Based on the fish you were keeping, you’re clearly also very experienced, which even underscores for anyone reading this just how big of a deal quarantine and disease are in this hobby. Thank you for sharing your story, because I think it will help others. It’s so natural and human…nothing went wrong so far…but it only takes one time. I let a similar thing happen (although with less cool fish).

      How does this story end, is there a happy healthy tank that you re-established? What would you say to the person who’s reading this that was just like you or me and thinking…yeah…but…

      1. I gave up on the hobby. Last year I began to look into setting up a saltwater aquarium. The big problem , and you or your readers might have some advice for me, is that my wife and I are both retired and are starting to travel. If we’re away for 2-3 weeks how is the aquarium to be cared for and maintained? One obvious thing you pointed out in one of your columns is to not have a full load of fish, to keep down the biomass load on the system. I have a neighbor with a freshwater aquarium but could he handle a marine system for 2-3 weeks? Does anyone board a hobbyist’s fish (for a fee)? Would an automatic feeder , properly loaded with correct portion size, contribute to a successful period with few if any problems while we’re away? There may be many people who never start this beautiful hobby because the wife says, “Who’ll watch the fish while we’re away?”

        1. Author

          Hi David,

          Thanks for the great comment. I’m sorry to hear that you gave up on the hobby–although I know it happens. It can be a challenge to have a saltwater tank if you travel a lot. In my opinion, a healthy, thriving saltwater tank can last a week of neglect, while you are travelling, without too much hardship–but I think if you are away for 2-3 weeks at a time and a few times a year that you probably made the right choice, although it was probably a tough choice.

          I think a common solution to travel is to hire a tank-sitter. Someone who could feed your tank and check on it a couple times while you’re out. What I do is try to make the tasks as simple and clear as possible and just depend on a neighbor. I pre-portion food and give detailed written instructions. but truthfully, I’m at a point in my life where 1 week away is the most I spend.

          If I was you, I wouldn’t second guess the choice. It sounds like you’re traveling a lot–and that wouldn’t be good for you or your tank. So kudos to you. If you decided you wanted to have a tank–I’d recommend you explore the notion of getting a tank-sitter to take care of the tank a bit while you’re gone.

          I like your idea of the fish boarding–but I haven’t heard of that yet. Does anyone else have a good solution for the argument…who will watch the fish while we’re away?

  3. 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. Author

      Hi Alan, this does create some complexity. I tend to shut my QT down if I know I won’t have any new fish for a while. I have extra sponge filters in my display tank sump. I take those out to jump start my QT. However, one other note that in my experience, the bacteria don’t ‘all die’ between fish. They are quite resilient between fish. I suppose if it was a very long time without organics they would die back. You could stoke that along by adding a pinch of food infrequently. Commercial ‘bacteria-products’ also boast faster cycle times if that helps

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