Keeping goldfish - it's not as easy as it seems!

Everyone's had a goldfish at some point in their lives. Maybe it was a prize at a funfair, or maybe it was a pet they could afford with their pocket money - or maybe it was simply the only pet their parents would let them have. Whatever the reason, goldfish are the most common pet in the world. But are they as easy to keep as we assume?

What exactly are they?

Goldfish are a small variety of carp, a type of freshwater fish, and the varieties we keep in bowls today are descended from a less-colourful carp variety from East Asia. However our tank-dwelling friends are related to the well-known carp varieties koi, kept in ponds all over the UK, and the crucian.Goldfish were first kept in a domestic setting in China over a thousand years ago. There are lots of breed variations with many different shapes, sizes and colours including orange, white, yellow and black.

Do they really have a three-second memory?

No! Tests have shown that goldfish have memories of at least three months and are actually quite intelligent creatures. Experts have proved that the fish can identify shapes, colours and even sounds and can even identify individual people. They may swim to the front of the tank and seem excited when their owner or the person that feeds them regularly, appears. Equally they might hide when approached by a stranger. Constant visual contact with humans will help them overcome their natural timidity - they may eventually allow their owner to hand feed them.Goldfish are outgoing creatures and will appreciate the company of another of their kind. They are not particularly aggressive and conflicts will generally only occur over food.

What equipment do I need?

One thing is for certain here - bowls are a no no! The age of keeping a goldfish in a large glass bowl is well a truly over. They do not allow adequate oxygenation, they are not large enough to enable a fish to swim naturally and they don't hold enough water to compensate for a goldfishes ammonia output. In fact, in some countries the keeping on goldfish in bowls is illegal.A good quality tank that holds at least 25 - 30 litres of water is recommended for one goldfish. This will be large enough to allow swimming and will cope with the mess created by your scaly critter. The tank should be fitted with a filter in order to keep the water clean and the fish in rude health. Another consideration is water quality. Water straight from the tap is full of chemicals to make it safe for humans to drink. If you are filling a tank with tap water it should be left to stand for several hours before you introduce your fish, to let the chemicals dissipate. Commercial neutralisers can also be purchased which can be added to tap water to make it immediately safe for your fish.Water temperature should also be carefully monitored as a goldfish can be easily shocked by water that is too cold or too warm. Your fish will probably be brought home in a bag so it's worth placing the bag in the tank water so the temperature can gradually equalise. Gradually add more and more tank water to the bag until it contains more tank water than bag water, then introduce your fish to his new home.Fish love to root for food in substrate so make sure you choose a gravel that is large enough not to be swallowed, but not too large that it can't be moved by the fish while he's hunting for food. Live plants add interest and can help oxygenate the water, while plastic plants can attract algae which oxygenates and provides an additional food source. Animated objects such as opening trunks, can also help oxygenate the water. If a fish is kept in the right conditions it could reach up to 60cm in length and live 20 years!

What to feed your fish

Commercially prepared, dried fish food is widely available and provides excellent nourishment for goldfish. However some varieties are sensitive to dried feed as it can swell in the stomach if they take it as soon as it enters the water. This can put pressure on the swim bladder which would cause balance issues. The best way to avoid this would be to soak the feed before you offer it to your pets. It is also important not to overfeed your fish as excess food will break down in the tank and dirty the water.Fish can be left unattended for a weekend as they will clear up any debris in the tank. If you are going away for any longer than this a food block can provide nutrition for your fish for up to two weeks.Fish are also partial to the odd worm. Dried bloodworms are available at most pet shops and should be soaked thoroughly before offering them to your pet - remember to only offer once a week as these are very high in protein and fat.

Changing the water

Even if you are using a good filter system the water in your tank will still need changing. Replace approximately one third of the volume once every three weeks. The water can either be bailed out, or a syphon device can be purchased. Again, any replacement water should not be fresh from the tap and the temperature should be as close as possible to that of the remaining water in the tank.

Goldfish benefits

Goldfish are beautiful creatures that cost very little to buy and maintain. Some people find watching fish extremely calming, and it is possible to build up a rapport with your pet - watch out for him swimming excitedly around the tank when he sees you coming!