There are actually relatively few things you need to keep a fish healthy. However, any fish will need these things, so keep them in mind when you are getting prepared for your new friends:

Although fish aren't really hard to care for, if you don't know a few basic facts you can doom the critters before they ever really have a chance

Fresh water fish are fish that spend some or all of their lives in fresh water, such as rivers and lakes, with a salinity of less than 0.05%.