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.
The lowering allows for the gold to fall out of the current of water. More times than not, gold will be found with other precious and non-precious metals. The gold must be extracted from these metals. The presence of gold in sea water is believed to be far greater than the presence anywhere else on earth.