Goldfish

For the Pepperidge Farm brand of snack crackers marketed in North America, see Goldfish (snack).

The goldfish (Carassius auratus) is one of the earliest fish to be domesticated, and is still one of the most commonly-kept aquarium fish. A relatively small member of the carp family (which also includes the koi and the Crucian carp), the goldfish is a domisticated version of a dark-gray carp native to East Asia (first domesticated in China) that was introduced to Europe in the late 17th century. It may grow to a maximum length of 23 inches (59.0 centimeters) and a maximum weight of 6.6 lb (3.0 kg), although this is rare: most individuals grow to under half this size.

Goldfish natively live in rivers, lakes, and other slow or still moving bodies of water in depths up to 65.6 ft (20 m). They natively live in a subtropical climate and prefer freshwater with a 6.0 – 8.0 pH, a water hardness of 5.0 – 19.0 dGH, and a temperature range of 32 to 106 °F (0 to 41 °C). Their diet consists of crustaceans, insects, and plant matter. They lay their eggs on aquatic vegetation.

Part of its popularity is due to the goldfish's hardiness. Their supposed reputation in some areas for dying quickly is often due to poor care amongst uninformed buyers, especially children, looking for a "cheap" pet. The goldfish is a cold-water fish, and can live in an unheated aquarium or in an outdoor water garden. In a pond, it will even survive brief periods of ice forming on the surface, so long as there is enough oxygen remaining in the water and the pond does not freeze solid. Although edible, the fish is rarely eaten.

Selective breeding has produced several colour variations, some of them far removed from the "golden" colour of the original. There are also different body shapes, fin and eye configurations. Such extreme versions of the goldfish do need to be kept in an aquarium — they are much less hardy than varieties closer to the "wild" original.

Goldfish and other carp fishes are frequently added to stagnant ponds in order to reduce the mosquito populations. Their introduction often has unfortunate consequences for local ecosystems, however.

Although goldfish were historically displayed in small "goldfish bowls", a healthy and happy goldfish requires at least ten gallons of water in order to live a full life. Each additional fish requires an additional five gallons (nearly 20 litres) of water. In fact, for single tailed varieties, such as commons or comets, it may even become necessary to have twenty to fifty gallons (75 to 200 litres) per fish, depending on size. While it is true that goldfish can survive in a fairly wide temperature range, the optimal range for indoor fish is 68 to 78 °F (20 to 22 °C). Pet goldfish will happily eat too much food if given, and thus can get a fatal intestinal blockage that will cause a painful death. They are omnivorous and do best with a wide variety of fresh vegetables and fruit to supplement a flake or pellet diet staple. Goldfish can only grow to sexual maturity if given enough water and the right nutrition. However if kept well, they may breed indoors. Breeding usually happens after a significant change in temperature, often in spring. Eggs should then be separated into another tank, as the parents will likely eat any of their young that they happen upon.

A fad among American college students for many years was swallowing goldfish as a stunt. The first recorded instance was in 1939 at Harvard University. The practice gradually fell out of popularity over the course of several decades.

In many countries, the operators of carnivals and fairs commonly give goldfish away in plastic bags as prizes for winning games. In the United Kingdom, the government proposed banning this practice as part of its Animal Welfare Bill, though early 2005 reports suggest that this idea has been dropped.

It is often said that goldfish have a memory span of only a few seconds, but this is not entirely true. Goldfish have what could be called a selective memory; that is to say, they have some kind of conscience of what has happened on previous occasions, but may not be sure exactly what it was. They can learn to eat from a certain ring inside their tank, or even from their caretaker's hand, because they will remember that there is something good in that area, but might not remember what. If a predatory animal such as a heron is around, they will likely hide away for quite a while, but they probably do not know what it is they are hiding from; they simply know it is worth avoiding. Goldfish have a sense of time, and in captivity may be able to recognize a set feeding schedule, becoming excited before food even appears.

There is an urban legend that a pregnant goldfish is called a "twit" or "twat", but this was debunked by The Straight Dope. Goldfish can not become pregnant, because egg fertilization occurs outside of the body.

Goldfish Varieties

• Black Moor
• Bubble Eye
• Celestial Eye
• Comet
• Fantail
• Lionhead
• Oranda
• Pearlscale
• Pompom
• Ryukin
• Shubunkin
• Telescope Eye

External links

• The Goldfish Sanctuary – Site of a now defunct goldfish rescue organization.
• Goldfish Paradise – Site that contains tons of information on goldfish care.
• BBC News Online – Goldfish are no longer to be given as prizes
• BBC News Online – Ban on goldfish prizes 'dropped'
• Very handy FAQ – Good FAQ's

• The Straight Dope – Is a pregnant goldfish called a twit?

References

• "Carassius auratus" (TSN 163350). Integrated Taxonomic Information System. N.p.: Integrated Taxonomic Information System, 2004. Accessed on 5 October 2004.
• "Carassius auratus auratus". FishBase. Ed. Ranier Froese and Daniel Pauly. September 2004 version. N.p.: FishBase, 2004.