Provide goldfish tank with a filtration system that is appropriate for size of tank. If you are keeping fancy tailed goldfish, don’t use a system that will provide too much current as this can make it difficult for them to swim around. You’ll also want to provide periodic water changes as you should with any tank.

One of main reasons that fish become sick is due to poor water quality. To keep your goldfish healthy, make sure you provide filtration and water changes but also be careful about overcrowding and overfeeding. Too many fish or too much decaying food and waste will cause water in your tank to become toxic to your fish.

Keeping goldfish can be a wonderful hobby and with minimal work, you can get a tank up and keep it running with healthy fish.

Lee Dobbins is owner and editor of epet-center.com – Your E Pet Center where you can learn more about keeping goldfish

The fish should interact well with another fish, as they pass each other, moving out, etc. Healthy fish should swim in a horizontal motion (not with its head up or down with a few exceptions) throughout aquarium---not just creeping around corners or hiding all time. Don’t pick a fish that allows itself to be bullied or likes to bully others! Spend some time watching fish you're interested in buying maybe a good advice. Sometimes you'll see things you didn't notice right away. Watch how it behaves for a while.

Only buy fish that eat well! If possible watch them being fed, as this is very important. You won’t have a wonderfully beautiful fish that only lasts a day, right?

It would be wise too to check fish prices. Unusually cheap price should be questioned, as there are some dangerous yet awfully cheap methods to caught fish today, like using cyanide and drugs. Cheap prices don’t have to mean poor quality.

And make sure that fish be caught with two nets. That’s best, since using one net will usually only result in a crazy chase around tank, making fish extremely stressed.