Petroleum, a fossil fuel, supplies more energy to the world today than any other source. The United States is the world's leading consumer of petroleum; in 1994, Americans used 7,587,000 barrels of oil per day.
Frequently test for ammonia and nitrite (you want both to measure zero). A pH test is also handy to ensure your goldfish's water is not too alkaline or acidic. This can be purchased at any pet store. Do not modify the fish's water, however, unless it is significantly different from neutral.
And a happy, healthy goldfish can live for decades! Soap is poisonous to fish and will kill them quickly, so don't wash your tank with soap. Also, don't use regular tap water to put in your tank. Drinkable water is not good for them because it takes out some of the minerals which are good for goldfish.