Quarantine tank setup with list of equipment needed and optional equipment recommendations
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Proper quarantine of new fish and even invertebrates is so important. The primary reason for quarantine is to prevent the spread of disease to your main tank. You can’t see parasites with the naked eye but if they get into your tank via a new purchase they could infect both it and all your other fish or corals.

In the worst-case scenario you could have a wipeout, losing all your precious collection to disease, and catching it too late to properly treat it.  A quarantine tank can also double as a hospital tank. If an existing fish starts to look sick in the main tank or is attacked by a tank mate, it can be moved to the hospital tank to be treated and to recover.

Conventional parasite treatments like Copper cannot be used on reef tanks because Copper is harmful to invertebrates like corals, shrimps and crabs. Parasites are themselves tiny invertebrates, and that's why when no other inverts are in the tank and a copper medication is used in a quarantine tank, it can be so effective.

“Reef safe” parasite treatments cannot contain anything that is harmful to corals, shrimps and other inverts, so are often limited in their effectiveness when used to treat disease in a typical reef tank.

Here’s what you need for a quarantine tank:

Tank size

A quarantine tank doesn’t have to be large and a 24” tank is fine for most fish up to 4” long.  For fish of 6-8” a 36” tank is necessary.  These numbers will, of course, change depending on how many fish you are planning to quarantine, but they are good general guidelines.

Bare Bottom

The bottom of the quarantine tank should be bare. Some parasite life cycles involve a substrate dwelling stage, so by removing any coral sand parasite numbers can be kept to a minimum.  Removing substrate will also prevent leftover food and other waste from collecting at the bottom, making it a whole lot easier to maintain water quality.

Mature Filter

An internal power filter should be used, but with media that has been matured in the sump of your main tank. As soon as you buy a new fish, set the tank up using main tank water and move the media into the power filter. Then you have a mature filter available at all times, and no risk of ammonia, nitrite and New Tank Syndrome, which will further stress an already sick fish.

Air Pump

Parasitic infections often cause breathing difficulties, and some medications can lower oxygen levels as well. Add an airstone powered by an air pump and your quarantine tank will always have high oxygen levels to aid recovery. Fit a new, sterile airstone each time and a check valve to prevent back syphoning


No tank lighting is necessary for a quarantine tank but a low voltage light can certainly be used.  Excessively bright light can stress a sick fish, break down medications, and cause algae growth.


Although we do our best to make quarantine a low-stress environment, fish will inevitably be stressed, especially when first introduced.  This paired with stress from potential parasites and medicine can easily turn any fish into a jumper.  Using a tight-fitting lid is a great way to ensure your fish's safety until they can be transferred to your main tank.


Tropical marine fish need a heater. Carry a spare heater to use in the quarantine tank when necessary. Fit a separate thermometer to monitor temperature accurately.

Tank background

A solid colour background and even tank sides and base may help a sick fish feel more secure and more at home.  This will limit the fishes exposure to the tank's surroundings, limiting potential stress factors.


Fish need somewhere to hide so a simple wide bore piece of PVC or abs pipe will be fine. It's easy to keep clean and sterilize after use too.  This is a cheap and easy solution to give your fish a little bit of comfort.

Other equipment

You’ll still need test kits for ammonia, nitrite and nitrate, to monitor that water quality in the quarantine tank is good at all times.  A refractometer is useful for monitoring salt levels as low salinity can be used to fight fish disease like Whitespot.  If you use Copper you need to monitor it with a Copper test kit. If you want to remove it afterwards (as it is not coral safe,) you’ll need copper removing chemical media too.

Heres what you can skip

Protein skimmer

Protein skimmers are not usually necessary for a quarantine tank as skimmers often skim off medications or other additives. The airstone will provide sufficient aeration instead.


Carbon removes many treatments so remove it from the internal filter.  Use mature biological media and mechanical filter media instead.


Ultra Violet Sterilization can be an effective weapon against fish disease but will break down medications and render them less effective. Use on the main tank but not in quarantine when treating fish.