An aquarium is a place where fish, water animals and water plants are kept. A goldfish bowl or a home fish tank are aquariums. There are bigger aquariums in many cities of the world. They are large buildings, very much like zoos, except that everything in them is a part of water life only. In the large aquariums the life in the huge water tanks is shown very much as it would be under natural conditions, in a lake or ocean. Many people have tanks full of brilliant- colored tropical fish. People with large homes in the country sometimes have outdoor aquariums.
These are usually small ponds in which fish, turtles and frogs are kept. An aquarium is a nice thing to have in the home, and it is easy to care for. There are certain things you must know, however, if you want to have an aquarium. If you are going to keep tropical fish, your aquarium must be heated. All other fish are kept in cold-water aquariums. A heated aquarium is necessary for tropical fish because they are used to living in warm water. The heat in a heated aquarium must be kept at the proper temperature. Otherwise the tropical fish will get sick and possibly die. Usually an electric light bulb or two will keep the water warm enough. An aquarium must be open at the top. The opening must be large enough so that air can reach the water.
The size of the opening depends largely on how many fish there are in an aquarium. The more fish, the larger the opening should be. Each fish in an aquarium needs a certain amount of oxygen. Some of this oxygen must get into the water from the air above it. An aquarium should have clean sand at the bottom. Small stones or shells should also be at the bottom. These stones and shells can be arranged in any attractive way. Next, an aquarium needs water plants. The plants should have their roots deep in the sand at the bottom of the aquarium. The fish for an aquarium should be carefully chosen. They should be the right size for the aquarium. The worst thing is to have fish that are too large for a tank, and do not have enough room to swim around.
Only fish that get along well together should be placed in an aquarium. No fish that fight or eat each other should ever be placed together. The fish in an aquarium will get some of their food from the plants, but other food will have to be placed in the water for them. If you have an aquarium, you must know the proper kind of food to feed your fish. You must also know how much food you must give to the fish. The wrong kind of food will cause the fish to get sick, and too little or too much food will do the same. You may think you are being nice to your fish if you feed them a lot. This is not true. You may do them great harm by overfeeding them. An aquarium should be clean before fish are put in it. It must be thoroughly rinsed with clear water.
Any trace of soap or disinfectant will be harmful to fish. Once fish have been put into the aquarium, it does not have to be cleaned. The plants in the aquarium will usually use up any of the waste matter from the fish. Sometimes small snails are put into an aquarium, because they help keep it clean. The snails are scavengers, which means they eat all the waste matter and bits of left-over food in the aquarium. Occasionally the water in an aquarium will evaporate, and the water level will go down. When fresh water is put into an aquarium to raise the water level, it must be the same temperature as the water in the aquarium. If you plan to have an aquarium in your home, the best thing to do is to find out from a pet-shop dealer what kind of fish he can sell you. When lie sells you the fish, he will tell you what to feed them, and other important things about keeping them. If one of the fish in your aquarium looks sick, take it out before it makes the other fish sick too. Find out from your dealer what is wrong with it, and keep it in a separate bowl until it is well again.