Goldfish are, perhaps, the most common first pet for a child. Unlike tropical fish, goldfish do not require quite as much in terms of aquarium supplies. They do not need a heater, for example, because they are cold water fish. They are also particularly hardy pets. However, unlike many people think, goldfish do require a bit of care. They cannot thrive in a fish bowl or tiny tank.
Goldfish need water that is below 73 degrees, and the water needs to be kept clean. While goldfish aquariums do not require heaters, they do require a thermometer, because you will need to watch for temperatures above 73.
Goldfish need at least 10 gallons of water, with at least 8 gallons per fish. This means that a 10-gallon tank can only hold one fish. Remember, the tiny goldfish you bring home from the pet store has the ability to grow to close to a foot in length, so give your fish plenty of room.
Change approximately ten percent of the water each week, so the fish has a clean environment. Aquarium pumps and aquarium filters do not completely clean the water, so water changes are absolutely necessary. Do keep the tank filtered, though, so that toxins do not build up in the water. Feel free to add aquarium decorations to the tank to make it look beautiful and give your fish somewhere to hide.
Goldfish cannot eat tropical fish foods. They need goldfish foods, because their dietary needs are different than most warm-water fish. It is very easy to overfeed goldfish, because they always "look" hungry. Feed your fish one time a day, but only give it the amount of food it can consume in two minutes. If you see leftover food, make the next feeding smaller, because rotting food will harm water quality. If you feed your fish more than once a day, your pet will produce more waste, which also harms water quality.
If you create a healthy aquarium environment for your goldfish and feed it quality goldfish foods, you can expect it to live for many years. It is not uncommon for a these fish to live up to ten years with a good setup. But whatever you do, do not stick your goldfish in a fish bowl!