阅读理解
Why keep them？
People keep dogs and cats because they enjoy their friendship．Fish cannot be friendly, but they have beautiful shapes and colours．They are pleasure to watch as they swim in their tanks(水槽)．
What do they need?
First of all, the fish need a suitable(合适的)tank, and you must fill the tank with suitable water．It is also good for them to have a few water plants in the tank to keep the water pure(纯净)．A few snails(蜗牛)in the tank are good idea, too．They will keep the water clean．
What about feeding them?
There are many kinds of fish food that you can get in pet shops．Most are suitable for all kinds of fish．You should feed your fish once a day only．It is important not to give them too much food．Just give them as much as they can eat in about 15 minutes．This will keep them healthy．
