Goldfish Heating and Lighting
Goldfish are cold water fish. Usually, there is no need for a heater in the tank, but make sure there are no drastic temperature changes in the room where the goldfish aquarium stands.
Goldfish do need light and so do the beneficial bacteria in the goldfish aquarium. Avoid putting your goldfish aquarium in direct sunlight - as it may heat the water too much. Instead, get a good light source above the goldfish tank. There is a great selection of fluorescent light strips available that fits right into the goldfish aquarium hood. Turn the light on for at least 8 hours a day, but make sure that the goldfish tank is darkened during night time. Remember, goldfish can't have no eyelids so they need to be in a dark environment to get a good night's sleep (and yes, they do sleep!).
Refer to the other pages in this section for more information about choosing the right goldfish aquarium, water filters and air pump, water plants and gravel and decorations.