How to Set Up a Quarantine Fish Tank

Setting up a quarantine (or hospital) fish tank is a great idea if you wish to become a serious fishkeeper.

Not only can you use it to isolate and treat sick fish, but you can also quarantine new fish until you are sure they are 100% healthy and disease-free.

You can also use it to quarantine new live plants to ensure they are free of pest snails. If you see any, you can treat the plants with a suitable solution to get rid of the snails before adding the plants to your tank.

Similarly, you can add any new corals to a quarantine tank before adding them to your main display tank to ensure they are free of aiptasia and other pests.

Diseases like Ich and Velvet can spread rapidly through your tank and kill your fish so it is vital that you can isolate and treat them quickly.

Let’s have a look at what you need to set up a quarantine fish tank.

Quarantine Fish Tank Size

A quarantine fish tank does not need to be large, a 45 – 50cm tank will suffice for freshwater fish and a 60cm tank for marine fish.

You’re not going to be bothered how it looks either, so an old, no longer used tank or a second-hand one will be fine, as long as it does not leak!

A starter tank kit would make a great quarantine tank. Take a look at our articles, Best Freshwater Fish Tank Starter Kit and Best Saltwater Fish Tank Starter Kit to give you some options.

Quarantine Fish Tank Equipment

Essentially, you’ll need some, but not all of the equipment required for a normal aquarium but it doesn’t need to be top of the range, just basic will do.

You’ll need a heater, for tropical fish, a filter, and basic lighting (though this is not absolutely necessary).

Lighting should be subdued and is only really required to help you spot signs of diseases like white spot (Ich) and velvet. Low lighting will also help prevent algae build-up.

You won’t need any substrate or rocks as these can harbour parasites and bacteria. Nor should you add any live plants or permanent corals for the same reason.

You can add a flower pot (or something similar) or even an artificial cave or plants for somewhere your fish can hide but be sure to clean them thoroughly on a regular basis.

You will also need a basic test kit to check levels of ammonia, nitrite and nitrate and a hydrometer to check salinity if it’s a saltwater tank.

Our articles, Best Test Kits for a Freshwater Fish Tank and Best Test Kits for a Saltwater Fish Tank will point you in the right direction.

You should never add carbon or any other chemical filter media as this will remove the beneficial elements of any medication you add to the quarantine tank to treat your fish.

Let’s summarise the equipment required for both a freshwater and marine quarantine tank.

Quarantine Fish Tank Cycling

Important: Before using your quarantine tank, you should make sure that it is cycled to ensure that harmful ammonia and nitrite (from fish waste) are biologically transformed into nitrates that are not harmful to your fish.

For more details on this process, please read our article on How to Cycle a Fish Tank.

You can pre-mature your quarantine tank filter by either running it first in your existing tank or by taking some media from your tank’s filter and adding that to your quarantine tank filter.

An easier way to speed up the cycling process is by using a bacteria supplement. Check out our article, Best Fish Tank Bacteria Supplements advising you on the best one.