Why Should You Quarantine Your Fish?

Quarantining in general is practiced in many situations by many institutions, such as zoos & public aquariums and customs control for the importing of animals, in order to prevent the spread of disease to an existing environment. Diseases aren’t always apparent, and time may be needed to conduct tests or to monitor a new animal to diagnose any possible diseases it may be harbouring. Professional quarantine procedures are essential to prevent the spread of disease.

If you take reefing seriously, quarantining your fish, invertebrates and other animals should be a must whenever you purchase or obtain new critters for your aquarium. You want to make sure your new fish are healthy before adding them to your display tank – you wouldn’t want to make  and any sick new fish are much easier to treat in a quarantine tank.

When quarantining, there are two main techniques – the quarantine and observe method, and the quarantine & medicate method.

Quarantining and observing fish without medicating them will put less stress on healthy (disease free) fish, and so long as they pass the quarantine period with no symptoms, they can be considered ‘disease free’.

However in my experience, about 8 in 10 fish bought home will develop some sort of disease. In the interest of saving time and having peace of mind, I treat all new fish to a medication regimen – regardless if they are showing symptoms or not. It is true that this can place unnecessary stress on a fish, however, most fish survive the medication and you will have peace of mind in knowing your fish is parasite and disease free.

A proper quarantine regimen will ensure that you protect your existing investment of fish in your display tank from diseases and parasites – which are highly contagious and often kill fish swiftly. Quarantining will also protect yourself from heartache and frustration, albeit at the expense of a little patience 😉

A sick fish with a severe case of Saltwater Ich, also known as Marine White Spot Disease. Caused by the parasite Cryptocaryon irritans.

Quarantine is important as fish or inverts purchased in fish or pet stores are not in their natural habitat; they are crammed into small confined tanks with dozens or in some cases, hundreds of other fish – all sharing the same water supply. It takes only one sick fish a few days to infect many other fish – so it is wise to consider all new fish from stores to be exposed to disease, and therefore, sick. All sick fish should be quarantined for observation and treated before addition into your main display tank.

A overstocked fish store – The perfect breeding ground for marine fish diseases & disease transmission

Quarantine tanks also allow you to acclimatise an animal in a more controlled setting, allowing you to acclimatise new tank additions without the disturbance of other tank-mates to encourage feeding. Additionally, quarantine tanks also function as treatment tanks for taking care of fish or inverts when they become sick. This is important, as most treatments for marine fish diseases affect water quality, and in some cases are even toxic to other animals such as inverts or corals, making treatment of a fish in a display tank impractical.

Cupramine, a popular copper based medicine, is essential when quarantining new fish, but is toxic to inverts.

Starting a new tank? Setting up a new tank with just corals, live rock and sand means you can skip medication treatments in most circumstances and leave the tank fallow as most fish diseases cannot survive without fish for more than eight weeks. After this period, you can add quarantined fish to your new tank.

If you have a new tank and you have also purchased fish, do not quarantine your fish in your main display tank, as residues from medicines, even in minute amounts, can be harmful to corals and inverts. This is extremely important when treating fish with copper based medications. Quarantine or treatment tanks must always be an independent tank, used only to treat sick fish or to quarantine new fish. Note that because inverts are sensitive to copper medications, inverts should be quarantined separately from fish.

A complete quarantine tank – PVC piping, temperature control, basic filtration & lighting.

Many hobbyists get lucky with their first few fish and setup a new tank without quarantining. The urge to add new additions to your display tank is usually strong – what would be better than to see all your new fish swimming around happily in your new tank. Try to resist this and follow quarantine procedures as if you don’t you will play a fool’s game of Russian roulette; each new fish added is potentially a carrier of deadly disease and will wipe out an entire tank. Save yourself money & heartache. Make quarantining a habit, and reef keeping will be a much more pleasurable hobby!

Next: How to set up a Quarantine Tank >>

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