Thus, goldfish are absolutely unsuited for life in bowls or small tanks. They are in fact the least suited of most commonly sold fish. If you want a bowl or small tank, keep small tropical fish with a heater or small coldwater fish without one. If you go so far as to desiring no electricity at all, a betta will do well in warm areas and a paradise fish in cooler areas. Even then, anything less than 2-5 gallons for a fish or two is cruel in my mind.
Bigger tanks are also easier to care for.
Life expectancies from 10-20 years are normal for well cared for fish. The oldest captive goldfish on record was Tish who is in the Guiness Book of World Records. His owner, Peter Hand of England, won him at the fair in 1956. Tish only grew to 4.5 inches long and was silver. Over the years we have become very close and I could sense if he was happy or not.