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.
I read somewhere totally scientific that goldfish will grow to a size commensurate with the size of their environment. So what if I filled a swimming pool with fresh water and all the bells and whistles they need to survive: filters, feeders, temperature regulators, aerators and what not, would I end up with dog-sized goldfish?