Pete the vet – How to look after your fishy pets

DO YOU KNOW what is the most popular pet in the country? Dog? Cat? Rabbit? Budgie? The answer may surprise you: the humble goldfish. Thousands of homes across Ireland have glass tanks and bowls, populated by small orange fish. Goldfish are cheap pets, and they're easy to keep. The big problem with goldfish in an indoor aquarium is that they live in a small volume of water which is completely controlled by humans: it's important to take steps to ensure that the water quality is as good as possible. Avoid overcrowding, ensure plenty of oxygenation, clean regularly, and above all else, do not overfeed the fish. A big enough tank is important. The rule of thumb is to allow twenty-four square inches of surface area of water to each one-inch length of fish. If you want more fish or if your fish grow bigger, you need to get a bigger tank. The tank should be put somewhere where it receives daylight but not direct sunlight. It can be kept in a room in the house or in the garage. As long as the temperature of their water does not change suddenly, goldfish are quite adaptable. Normal tap water is fine for goldfish but you should remove the chlorine by adding a few drops of special dechlorinating liquid that you can buy in a pet shop. A plain tank needs a little 'dressing up' to make it suitable for fish. Most people add a layer of gravel to the floor of the tank: goldfish seem to enjoy rummaging around in the small stones. You can also provide a few pieces of 'furniture' for your fish. You can choose a few rocks, pieces of wood, or you can even buy special plastic shapes designed to decorate an aquarium (eg ship wrecks, houses etc). It is best to use only objects designed for immersion into goldfish tanks. The wrong types of rock, wood or toys may dissolve in the water, poisoning your fish. It also is a good idea to add a few plants: goldfish enjoy swimming among them. Plants also help to keep the water clean, and produce oxygen in the daytime. You can get plastic plants, but obviously they do not fulfil the function of producing oxygen. Many people have successful goldfish tanks without any extra paraphernalia other than the above. However, the one extra item that is worth considering is a simple electric pump. This can provide the double function of filtration and aeration, which helps to keep the water fresh and oxygen-rich. Fish tanks do need regular cleaning out. Generally, a partial water change should be done every few weeks, removing and replacing a quarter of the total volume of water. Every six months, the entire tank should be thoroughly cleaned to remove all algae and debris. Goldfish are easy to feed. The standard food is formulated as flakes or pellets, made of a mixture of ingredients containing everything the goldfish needs.  The biggest mistake made by beginners is to feed their goldfish too much food. Uneaten food sinks to the bottom of the tank and goes rotten. The tank then becomes dirty, and the fish die.  You must 'feed the fish' â€â€ do not 'feed the tank'. Never give more food than the goldfish will eat as you watch them for about two minutes. If there is any food left after five minutes, then you have given too much. You can feed them once a day, or twice a week. There are no strict rules about frequency of meals. If you follow the above basic rules of goldfish-keeping, they can be wonderful pets that live for many years.