How to Buy a Goldfish

Buy a tank, set it up and leave it to stabilize before you add any fish. Never buy a new tank and goldfish on the same day. All new aquariums must go through the nitrogen cycle before the water is safe. This is a natural process that produces harmful ammonia, nitrate and nitrite until the good bacteria in your tank can get to work and stabilize the environment.

Add a commercial beneficial bacteria solution to your tank. The nitrogen cycle takes roughly four weeks but you can cut that down to a week if you use some friendly bacteria to kick start the cycle and have your new fish safely moved in a lot sooner.

Invest in a set of water testing kits; these really are lifesavers, because you can’t see or smell any of the toxic chemicals produced during the nitrogen cycle. Test for ammonia, nitrate and nitrite once a week and check the color test strip against the chart in the box so you can be absolutely sure when it’s safe to get your goldfish.

Choose a pet store by reputation rather than the size of the company or how cheaply it sells goldfish. Big chains have a swift turnover of fish, so the critters in the store tanks probably haven’t been in there more than a couple of days, which means they may still be stressed from transportation. However, large stores usually have very robust water treatment methods in place to prevent disease and maintain optimal fish health.

Ask friends and family and browse local fish forums on the Internet for an unbiased opinion of fish at a particular store, if you’ve never shopped there before. Aquarists are always keen to impart their knowledge and recommend a good aquatics department. Similarly, if you see multiple bad reviews of a pet store’s fish section, it may be wise to steer clear and find somewhere else.

Browse the whole aquatics department for a good idea of whether their fish are in good health. Don’t be put off by a sign proclaiming "These fish are under quarantine and are not for sale" on the front of the tank. It looks super scary, but a good aquatics department quarantines all new fish before releasing them on sale, ensuring newcomers are disease-free and ready for a new home. However, more than one tank stating "Fish under treatment" is an entirely different matter and indicates there is a disease problem at the store.

Avoid any fish that look sick, injured or generally unhealthy. Signs of disease include gasping at the water’s surface, raised scales, a bloated body, bulging eyes, torn or bruised fins and small white spots that look like grains of salt.