........In the wild, your fish would live in a much larger body of water in which nature would filter out waste materials. In your aquarium, however, the single greatest killer of fish is the build up of waste materials, those excess food and fish wastes which must be filtered out or changed into harmless compounds to prevent poisoning of your fish.

The basic item for the home aquarium is the container to house your fish. There are many tanks on the market today. Tanks made of glass or plastic tanks in all shapes, and some that even double as coffee tables or lamps. But, whatever tank you choose, you will need the same basic equipment: a tank with a hood containing a light source to control the length of day and season, a heater to control the temperature, and a filtration system to aerate and clean the water.

One of the best filters for the conversion of waste is the undergravel filter, a plate with water lift tubes that is placed under the aquarium gravel. Water is drawn down through the gravel and up through the lift tubes causing the waste to be trapped in or filtered through the gravel, where bacteria can convert the wastes into harmless compounds. Another type of filter is the outside power filter, which operates outside of the aquarium and pulls water from the tank and filters this water though a medium of sponge foam and charcoal, before returning it to the tank. Outside power filters remove large, floating waste particles from the water and are recommended when messy fish, like goldfish, are kept. Many people prefer a combination of an under-gravel filter (for bacterial action), and an outside power filter (to remove large waste particles); this combination makes tank upkeep much less work.

Your choice of fish is a matter of personal preference, but there are a few basic rules to follow: Do not put too many fish in your tank, overpopulation stress fish and is the no.1 cause of disease and other problems. Buy inexpensive tropical fish for your first try, so that if the fish dies, you are not bankrupt! Choose fish that require the same water conditions, temperature and food, not fresh and salt water fish together, for example. Buy young fish and watch them grow. Immature fish cost less and small fish are less likely to over crowd your tank. Make sure your fish will grow up to be the same size, large fish will eat smaller fish. Choose compatible fish. You do not want territorial or combative fish chasing (or chewing on) milder ones. Do not buy your tank and your fish at the same time. Get your tank and set it up and then buy your fish.

Last, but not least, do not rely on scavengers to eat excess food or fish waste. If you over feed your fish, the food will spoil and foul your tank. Only feed your fish the amount of food they can eat in five minutes. Feed them once or twice a day. Remember that, healthy and hungry fish are active fish.

The care and upkeep of your tank will depend on your filtration system and the number of fish you have. If your filter controls the poisons caused by fish wastes, you will only have to replace water lost through evaporation and do a basic clean up and one-third water change about once a month. If you over feed your fish or have an inefficient filtration system (like a small, inside corner filter), you have to change your water more often to keep your fish happy and healthy.