INTRODUCTION:
History
Starting in ancient China,
various species of carp (collectively
known as Asian
carps) have been domesticated and
reared as food
fish for thousands of years. Some of these normally gray or
silver species have a tendency to produce red, orange or yellow color mutations; this was
first recorded in the Jin Dynasty (265–420)
During the Tang Dynasty (618–907),
it was popular to raise carp in ornamental ponds and water gardens. A
natural genetic mutation produced gold (actually yellowish orange) rather than
silver coloration. People began to breed the gold variety instead of the silver
variety, keeping them in ponds or other bodies of water. On special occasions
at which guests were expected they would be moved to a much smaller container
for display.
By the Song Dynasty (960–1279),
the domestication of goldfish was firmly established. In 1162, the empress of
the Song
Dynasty ordered the construction of a pond to collect the red
and gold variety. By this time, people outside the imperial family were
forbidden to keep goldfish of the gold (yellow) variety, yellow
being the imperial color. This is probably the reason why there are
more orange goldfish than yellow goldfish, even though the latter are
genetically easier to breed.
During the Ming Dynasty (1368-1644),
goldfish also began to be raised indoors, which led to the selection for
mutations that would not be able to survive in ponds. The occurrence of
other colors (apart from red and gold) was first recorded in 1276. The first
occurrence of fancy-tailed goldfish was recorded in the Ming Dynasty. In
1603, goldfish were introduced to Japan, where the Ryukin and Tosakin varieties
were developed. In 1611, goldfish were introduced to Portugal and
from there to other parts of Europe.
During the 1620s, goldfish were highly regarded
in southern Europe because of their metallic scales, and symbolized good luck
and fortune. It became tradition for married men to give their wives a goldfish
on their one-year anniversary, as a symbol for the prosperous years to come.
This tradition quickly died, as goldfish became more available, losing their
status. Goldfish were first introduced to North America around
1850 and quickly became popular in the United States.
Controversy over proper treatment:
In many countries, carnival and fair operators commonly give goldfish away in plastic bags as prizes. In late 2005 Rome banned the use of goldfish and other animals as carnival prizes. Rome has also banned the use of "goldfish bowls", on animal cruelty grounds. In the United Kingdom, the government proposed banning this practice as part of its Animal Welfare Bill,though this has since been amended to only prevent goldfish being given as prizes to unaccompanied minors.Some countries b an the sale of traditional fishbowls under animal welfare legislation due to the risk of stunting, deoxygenation and ammonia/nitrite poisoning in such a small environment.Because of their large oxygen needs and high waste output, such bowls are no longer considered appropriate housing for goldfish.
In Japan, during summer festivals and religious holidays (ennichi), a traditional game called goldfish scooping is played, in which a player scoops goldfish from a basin with a special scooper. Sometimes bouncy balls are substituted for goldfish.
Although edible, goldfish are rarely eaten. A fad among American college students for many years was swallowing goldfish as a stunt and as a fraternity initiation process. The first recorded instance was in 1939 at Harvard University.The practice gradually fell out of popularity over the course of several decades and is rarely practiced today.
In aquaria:
Like most carp, goldfish produce a large amount of waste both in their faces and through their gills, releasing harmful chemicals into the water. Build-up of this waste to toxic levels can occur in a relatively short period of time, and can easily cause a goldfish's death. For common and comet varieties, each goldfish should have about 20 US gallons (76 l; 17 imp gal) of water. Fancy goldfish (which are smaller) should have about 10 US gallons (38 l; 8.3 imp gal) per goldfish. The water surface area determines how much oxygen diffuses and dissolves into the water. A general rule is have 1 square foot (0.093 m2). Active aeration by way of a water pump, filter or fountain effectively increases the surface area.
The goldfish is classified as a cold water fish, and can live in unheated aquaria at a temperature comfortable for humans. However, rapid changes in temperature (for example in an office building in winter when the heat is turned off at night) can kill them, especially if the tank is small. Care must also be taken when adding water, as the new water may be of a different temperature. Temperatures under about 10 °C (50 °F) are dangerous to fancy varieties, though commons and comets can survive slightly lower temperatures. Extremely high temperatures (over 30 °C (86 °F) can also harm goldfish. However, higher temperatures may help fight protozoan infestations by accelerating the parasite's life-cycle—thus eliminating it more quickly. The optimum temperature for goldfish is between 20 °C (68 °F) and 22 °C (72 °F).
Like all fish, goldfish do not like to be petted. In fact, touching a goldfish can endanger its health, because it can cause the protective slime coat to be damaged or removed, exposing the fish’s skin to infection from bacteria or water-born parasites. However, goldfish respond to people by surfacing at feeding time, and can be trained or acclimated to taking pellets or flakes from human fingers. The reputation of goldfish dying quickly is often due to poor care. The lifespan of goldfish in captivity can extend beyond 10 years.
If left in the dark for a period of time, goldfish gradually change color until they are almost gray.Goldfish produce pigment in response to light, in a similar manner to how human skin becomes tanned in the sun. Fish have cells called chromatophores that produce pigments which reflect light, and give the fish coloration. The color of a goldfish is determined by which pigments are in the cells, how many pigment molecules there are, and whether the pigment is grouped inside the cell or is spaced throughout the cytoplasm.
Because goldfish eat live plants, their presence in a planted aquarium can be problematic. Only a few aquarium plant species for example Cryptocoryne and Anubias, can survive around goldfish, but they require special attention so that they are not uprooted. Plastic plants are often more durable, but the branches can irritate or harm a fish that touches one.
FOOD:
In the wild, the diet of goldfish consists of crustaceans,insects, and various plant matter. Like most fish, they are opportunistic feeders and do not stop eating on their own accord. Overfeeding can be deleterious to their health, typically by blocking the intestines. This happens most often with selectively bred goldfish, which have a convoluted intestinal tract. When excess food is available, they produce more waste and faces, partly due to incomplete protein digestion. Overfeeding can sometimes be diagnosed by observing faces trailing from the fish's cloaca.
Goldfish-specific food has less protein and more carbohydrate than conventional fish food. It is sold in two consistencies—flakes that float, and pellets that sink. Enthusiasts may supplement this diet with shelled peas (with outer skins removed), blanched green leafy vegetables, and bloodworms. Young goldfish benefit from the addition of brine shrimp to their diet. As with all animals, goldfish preferences vary.
Related species:
Previously, some sources claimed the Crucian carp (Carassius carassius) as the wild version of the goldfish. However, they are differentiated by several characteristics. C. auratus have a more pointed snout while the snout of a C. carassius is well rounded. C. gibelio often has a grey/greenish color, while crucian carps are always golden bronze. Juvenile crucian carp have a black spot on the base of the tail which disappears with age. In C. auratus this tail spot is never present. C. auratus have fewer than 31 scales along the lateral line while crucian carp have 33 scales or more.
When found in nature, C. auratus gibelio are olive green. Introduction of goldfish into the wild can cause problems for native species. Goldfish can hybridize with certain other species of carp. Within three breeding generations, the vast majority of the hybrid spawn revert to their natural olive color. The mutation that gave rise to the domestic goldfish is also known from other cyprinid species, such as common carp and tench. Koi may also interbreed with the goldfish to produce a sterile hybrid fish.
There are many different varieties of domesticated goldfish. Fancy goldfish are unlikely to survive in the wild because of their bright fin colors; however the hardier varieties such as the Shubunkin may survive long enough to breed with wild cousins. Common and comet goldfish can survive, and even thrive, in any climate that can support a pond.
