One of the first things you need to be aware of when caring for goldfish is the water temperature. If the water is too cold your fish won't survive very long, and if it's too hot it can kill them almost instantly. You have to have just the right temperature for your common goldfish to thrive in. Another aspect is the water salinity. This is the amount of salt, or sodium, that you have in your water. Some cities have sodium added to their water system, so if you are planning on using your tap water to fill your goldfish bowl, you should make sure that the salinity in your water is low enough for your common goldfish. Once you have these basics down, it's all about keeping the bowl or tank clean and feeding.
