Reasons to keep a quarantine tank for your fish

Fish can make rewarding pets, but they need careful care. One of the most useful things any fish keeper can do, whether you keep a marine set-up or a couple of goldfish, is to have a quarantine tank. New fish should never go straight into your main tank, where they could pass on disease to your other fish.

What a quarantine tank is for

A quarantine tank is a separate, spare tank kept ready for whenever you need it. It has several uses.

Checking new fish

Some health problems aren't visible straight away, even in fish that look healthy when you buy them. Keeping new fish in a quarantine tank gives you time to watch them closely for any signs of illness or parasites before they meet your other fish.

Isolating sick fish

If a fish becomes unwell and needs treatment, a quarantine tank lets you separate them from the rest. This helps stop illness spreading and gives the sick fish a quieter place to recover.

Emergencies in the main tank

If something goes wrong with your main tank, such as the filter breaking or the heater failing, you can move your fish to the quarantine tank while you fix the problem.

Protecting young fish

A spare tank can also be used to protect the young of livebearing fish, such as guppies, from being eaten.

Keeping it ready

A quarantine tank is most useful if it can be used at short notice. Setting up a new tank from scratch, with the right water and temperature, takes time, and a sick fish may not have that time.

Keep a cycled filter or filter sponge running in your main tank so the quarantine tank can be set up quickly with healthy bacteria.

Setting up the tank

A quarantine tank is usually fairly cheap to run. It can be smaller than your main tank, but should be large enough for the fish it holds, with matching water temperature and quality. Matching the conditions makes moving fish between tanks smoother and less stressful for them.

You don't need decoration. The tank is there to do a job, not to look good.

Cleaning after use

After housing sick fish, clean and re-cycle the tank before using it again. This stops germs from one illness passing to the next fish. Never put new fish into water that has held sick fish.

How long to quarantine new fish

Keep new fish in quarantine for at least two to four weeks. Watch them closely during this time, and only add them to your main tank once you are happy they are healthy.