How to Quarantine

How to Setup a Quarantine Tank

The following are the bare essentials:

  • Aquarium (10-30 gallons seems to work for most people. Bigger QT lets you house more fish and gives you more wiggle room when it comes to ammonia. Smaller QT is cheaper, easier to maintain and can be setup/broke down quickly.)
  • Heater and thermometer
  • Small powerhead or air pump and sponge filter, for circulation & gas exchange.
  • Freshly mixed saltwater which has been fully dissolved and circulating for at least 24 hours.

Optional/recommended equipment:

  • Light (can just be a simple, one bulb fixture)
  • Hang on the back (HOB) power filter, where a “seeded” sponge (explained later) can be added
  • Egg crate (used on lighting panels), which can easily be cut with snips to build a custom top to prevent fish from jumping
  • PVC elbows (see pic below) used as “caves” in which the fish hide
  • Seachem Ammonia Alert badge (see pic below)

Scenario 1 (Simple QT with air pump + sponge filter):

Scenario 2 (More elaborate QT with HOB power filter – Seachem Tidal, Aquaclear and Bio-wheel are all good options):

A small amount of sand is fine in QT, but rock is best avoided as it will absorb many medications. However, one or two small pieces of live rock may be added for ammonia control, so long as they are coming from a disease-free tank. The live rock will need to be removed once a disease is spotted and before medications are used. Furthermore, the live rock must be considered “contaminated” once exposed to a fish disease, and sterilized in a chlorine:water (1:10 ratio) solution. Using a lid is very important to prevent fish from jumping out. As mentioned previously, egg crate can be used, but sometimes it is necessary to sew screen under the eggcrate top to prevent small fish from jumping through the holes:

Ammonia Control & Oxygen

Toxic ammonia, caused by fish urine/poop and uneaten food, needs to be closely monitored in QT. You can use a test kit (so long as no medications are present) or a Seachem Ammonia Alert badge (works even in the presence of medications.) Even the smallest traces of ammonia are toxic! 

In Scenario 1, performing water changes is your best option for controlling ammonia. You can also use an ammonia reducer such as Amquel or Prime provided no medications are present in the water. Copper, in particular, can be converted from a stable form to a more toxic form when mixed with an ammonia reducer. If you need to condition tap water, do so 48 hours prior to dosing copper.

With Scenario 2 the use of “seeded” bio-media can help to break down ammonia. I personally use a Seachem Tidal power filter, utilizing the “Matrix” bio media that comes with it. Similarly, Aquaclear contains a foam insert and the Bio-wheel itself can be seeded with nitrifying bacteria for use as biological filtration in QT. Bio media can be seeded with live bacteria in one of two ways:

  1. Place it in a high flow area of your DT’s sump (or you can put it behind the rocks) for at least one month prior to QT. This one month allows time for enough beneficial bacteria to transfer over.
  2. Dose a “bacteria in a bottle” product, such Bio-SpiraSeachem Stability or Dr Tim’s Nitrifying Bacteria, into the QT a few days before purchasing fish. Below are pics of bio-media discussed which can be seeded with live bacteria – Seachem Matrix, Aquaclear’s foam insert and the Bio-wheel, respectively:

It is also crucial to provide sufficient gas exchange (oxygen) in QT, especially when using medications. One can accomplish this by creating a “disturbance” at the surface of the water by using a sponge filter, pointing a powerhead upwards or via HOB power filter:

Quarantine Protocols

Some prefer to just observe in quarantine and not use any medications unless necessary. This strategy can work, but it is important to set aside enough time in your day to observe for key behavioral symptoms of disease. These include loss of appetite, heavy breathing, scratching, flashing, head twitching, erratic swimming behavior, swimming into the flow, etc. Of course, also look for visible physical symptoms of disease: white dots or growths, dark spots, red sores, frayed fins, etc. If treatment is needed, ensure you can quickly transform your “observation tank” into a “hospital tank” – one without rock, UV, carbon, poly filter, etc. which will absorb medications. Alternatively, you can transfer the fish to a hospital tank for treatment – provided it is at least 10 feet away to account for aerosol transmission.

A once popular QT protocol is tank transfer method. However, the recent prevalence of Marine Velvet Disease can make this a risky proposition. It is thought that TTM can delay symptoms of velvet from showing, because the transfers keep the number of velvet trophonts on the fish at a sublethal concentration.

My personal QT regimen is a lot more aggressive, as I have first-hand knowledge of just how polluted the supply chain is with disease. Therefore, below are two options you can employ to closely mirror my QT protocol:

Option A – Fish is floated in the bag for 20-30 minutes (to temperature acclimate) and then released into QT with matching salinity. QT is predosed with one of the following:

1. Copper Power at 1.0 ppm, verified using the Hanna Instruments High Range Copper Colorimeter (HI702). Over the next 48 hours, slowly raise your copper level to 1.5 ppm in gradual increments. Then take another 48 hours to raise it to 2.0 ppm. And another 48 hours in order to achieve 2.5 ppm. (So 6-7 days total to raise the copper level from the initial 1.0 to full therapeutic 2.5.) You are now at a safe therapeutic copper level. Add to this metronidazole. If using 100% metronidazole powder, dose 25 mg per gallon. Otherwise follow the maximum dosing instructions for whatever product (e.g. Seachem Metroplex) you are using.


2. Chloroquine phosphate (pharmaceutical grade) at 15 mg/L or 60 mg per gallon. This is a therapeutic Chloroquine level.

The above prophylactically treats most parasites if held at a therapeutic concentration for 30 days. Therefore, it is important to test your copper level frequently. If the level drops below therapeutic (1.5 ppm is the minimum for Copper Power) even slightly, the 30 day clock restarts after you’ve raised it back up. Therefore, when doing a water change dose any new water with copper or Chloroquine before it is added to the tank. After 30 days you can perform water changes and/or run carbon, Cuprisorb, poly filter, etc. to remove the medication(s).

It is now time to move on to deworming your fish. Two options for doing this: API General Cure or Prazipro. Dose once, and in 5-7 days do a 25% water change and dose again. (Or use this treatment calendar to determine when is the best time to add the second dose.) The reason for the second dose is to eradicate the “next generation” of worms before they can lay eggs of their own. Because while Prazi does kill worms, it doesn’t eliminate any eggs they might leave behind. You can technically mix General Cure or Prazipro with copper, but only General Cure can be safely combined with Chloroquine. The risk associated with combining medications is a bacterial bloom (cloudy water) which can starve oxygen out of the water. To alleviate this risk, always point a powerhead towards the surface of the water or run an air stone on high whenever mixing medications.

After 30 days in copper or Chloroquine + being dewormed, your fish should be observed in non-medicated water for at least another 2 weeks. This is to ensure the treatments you applied were successful, and also observe for less common diseases (more info below).

Option B – Everything works the same as “Option A” except the fish is transferred into another QT (or holding tank) after 2 weeks. However, the following “rules” must be strictly adhered to:

1. Only the fish gets transferred, nothing else. Meaning, do not use ANYTHING from the treatment tank to setup the holding tank.
2. DO NOT lower the copper or Chloroquine level prior to transferring.
3. The “holding tank” must be at least 10 feet away from the QT, Display Tank and all other saltwater aquariums.
4. The two week countdown does not begin until copper or Chloroquine have reached therapeutic, and have been maintained at therapeutic throughout (very important!) So, it is wise to test your copper level often.
5. Prior to transfer, the fish should not be showing any signs of ich, velvet, brook or uronema. If he does, don’t do the transfer!

The above works because parasites can only stay on a fish for a maximum of 7 days, and the presence of therapeutic copper + metro or Chloroquine shields your fish from reinfection. (The additional 7 days allows for some margin of error.) Any parasites the fish was carrying will have dropped off and are left behind in the original treatment tank. (So the QT that the fish is transferred from may still be contaminated with disease for some time.) After transferring you may deworm (if you hadn’t already done so in QT#1) or dose other medications as needed. I recommend observing for at least 2 weeks before transferring any fish to your display tank.

Don’t hesitate to make changes to your treatment plan as needed! For example, if you know a fish has flukes treat with Prazipro or General Cure first. Notice white stringy poo coming out of your fish? Start food soaking General Cure, using a binder such as Seachem Focus to reduce the loss of medication to the water through diffusion. Seeing signs of a bacterial infection? Treat with antibiotics straight away (you can combine most antibiotics with copper or Chloroquine.)

Less Common Diseases

The following is a brief rundown of less common diseases you may encounter in QT (and what to do about them!). Blue words contain links to more detailed information.

1. Internal flagellates/intestinal worms (white stringy poop): Food soak API General Cure for 2-3 weeks, or until “normal” poo is observed coming out of the fish. Here’s how, using a shot glass to more effectively concentrate everything:

1 scoop (~ 1/8 teaspoon) of medication
1 scoop Seachem Focus (this makes it reef safe)
1 tbsp food (preferably pellets or frozen food)
A pinch of Epsom salt to help expel dead worms/parasites
A few drops of saltwater or fish vitamins
Stir until a medicated food slurry has been achieved.
Feed after soaking for 30 mins.
Refrigerate or freeze any leftovers for future use.

2. Bacterial infections (red sores, discolorations): Treat with antibiotics.

3. HLLE and Lymphocystis: Click on words/links for more info.

4. Brook and Uronema: Click on words/links for more info.

5. Prazi resistant flukes: Hyposalinity for 1 week, formalin, or fenbendazole.

6. Prazi resistant intestinal worms: Fenbendazole (via food soaking).