The common goldfish, also known as feeder fish, is a type of goldfish with no other differences from their ancestors other than their color. Goldfish are a form of domesticated wild carp and are a close relative of koi. Most varieties of fancy goldfish were derived from this simple breed.
https://en.wikipedia.org/wiki/Common_goldfish
Goldfish Size and Life Expectancy. If kept in a suitable environment, single tail goldfish normally grow to 10 inches (25cm) and can sometimes reach 12 inches (30cm). Fancy goldfish normally grow to 8 inches (20cm). The normal life expectancy of a single tail goldfish is about 20 years.
http://www.fishkeeping.co.uk/articles_74/goldfish-size-life-expectancy.htm
All too often, carnival goldfish find themselves living in small bowls eating bits of dog food or dried bread. Unless you change the water completely every day or two and provide proper nutrition through goldfish pellets, your pet fish probably won't live more than a week.
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Without an aquarium setup, a carnival goldfish may die in a few days. Digital Vision/Photodisc/Getty Images. Summer carnivals bring colorful booths lined with games of chance, offering participants a chance to take home a prize.
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Goldfish will die without sufficient dissolved oxygen in the water. A filter that can do at least 10x filtration is best, which means that for every 10 gallons or litres of water, the filter should be able to cycle 100 gallons or litres per hour.
https://en.wikipedia.org/wiki/Common_goldfish
Long-Term Survivors. If you're willing to invest in the long-term needs of your carnival goldfish, he may live in excess of 20 years. The longest-lived known carnival goldfish was won from a fair in Yorkshire, England in 1956. The fish lived until 1999, dying at the age of 43 years old.
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Like the maximum size, the lifespan of goldfish is also variable. The record is 43 years, but it is uncommon for goldfish to live this long. Goldfish usually live quite long when kept in large aquaria or outdoor ponds, up to 15 to 20 years is not unheard of. In smaller or heated aquaria, a lifespan of five to ten years is quite achievable.
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Answers. Relevance. Rating Newest Oldest. Best Answer: Up to 15 years for a fancy, and an average of 25 years for a common, but for them to reach those ages, you need serious filtration of DOUBLE the tank capacity. Commons need a tank of at least 55 gallons per fish (or a pond). Fancies need at least 30 gallons for 2 fish.
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If you've just bought the fish or tank take them back to the shop and ask for a refund. Tanks too small for goldfish are not fit for purpose so you are legally entitled to a refund. Re-home the fish-single tail goldfish are more suited to a pond but don't transfer them in the winter.
http://www.fishkeeping.co.uk/articles_74/goldfish-size-life-expectancy.htm
Fancy Goldfish: 30 gallons (36 US gallons, 140 litres) for the first fish with an extra 10 gallons (12 US gallons, 45 litres) for each extra fish. The tank needs to have a minimum length of 3 feet to allow swimming room. In addition, an external filter is highly recommended.
http://www.fishkeeping.co.uk/articles_74/goldfish-size-life-expectancy.htm
what is a lifespan of a goldfish
A lifespan of a goldfish is for 20 years.