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Goldfish
Conservation status
Template:StatusSecure
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Carassius
Species: C. auratus
Subspecies: C. a. auratus
Trinomial name
Carassius auratus auratus
(Linnaeus, 1758)
For the Baked Snack Crackers, please see Goldfish (snack).

The goldfish (Carassius auratus auratus) was 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 carp and the crucian carp), the goldfish is a domesticated version of a dark-gray/olive/brown 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 cm) and a maximum weight of 6.6 pounds (3.0 kg), although this is rare; most individual goldfish grow to under half this size. In optimal conditions, goldfish may live more than 20 years (the world record is 49 years); however, most household goldfish generally only live six to eight years.

History

During the Tang Dynasty, it was popular for Chinese ponds to have carp. As the result of a genetic mutation one of these carp displayed "gold" (actually yellowish orange) rather than silver coloration. This mutation is associated with a dominant gene which also makes the breeding of this trait rather easy. The gold strain became popular for keeping in containers. Afterwards, the people began to breed the gold variety instead of the silver variety, and began to keep them in small containers to watch.

In 1162, the empress ordered the building of a pond to collect the red and gold variety of those carp. By this time, people outside the royal family were forbidden to keep goldfish of the gold (yellow) variety. An order was given to the keepers to kill all fish that were yellow in color because it offended the court, since this itself was the royal color. This probably is the reason why there are more orange goldfish than yellow goldfish, even though the latter are genetically easier to breed.

Since goldfish were bred in captivity, more mutations occurred, and therefore produced more colors. As a result, fancier varieties of goldfish appeared. According to old books and records, the occurrence of other colors were first recorded in 1276. The first occurrence of fancy tailed goldfish was recorded in the Ming dynasty. In 1502, goldfish were introduced to Japan, where the Ryukin and Tosakin varieties were developed.

In 1611, goldfish were introduced to Portugal and from there, they were introduced to other parts of Europe. Goldfish were first introduced to North America in 1874 and quickly became popular in the United States.

Varieties of domesticated goldfish

Selective breeding over centuries has produced several color variations, some of them far removed from the "golden" color of the originally domesticated fish. There are also different body shapes, fin and eye configurations. Some 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, however more robust variations such as the Shubunkin are more hardy. The main varieties are:

Goldfish Being Scooped Up

Chinese Goldfish classification

In Chinese goldfish keeping, goldfish are classified into 4 main types, which are not commonly used in the west.

  • Dragon Eye - Goldfish with extended eyes, e.g. Black Moor, Bubble Eye, and Telescope Eye
  • Egg - Goldfish without a dorsal fin. e.g. Lionhead (note that a Bubble Eye without a dorsal fin belongs to this group)
  • Wen - Goldfish with dorsal fin and a fancy tail. e.g. Veiltail
  • Ce (may also be called "grass") - Goldfish without anything fancy. This is the type that is used for Japanese carnivals, especially for "goldfish scoops".
  • Jikin and wakin - two goldfish with a double tail, but with the body shape of a comet.

Goldfish in ponds

File:Pfish.jpg
Goldfish pond

Goldfish can also be kept in ponds. Common goldfish, London and Bristol shubunkins, Jikin, Wakin, comet and sometimes fantail can be kept in a pond all year round in temperate and subtropical climates. Moor, veiltail, oranda and lionhead are only safe in the summer. Goldfish make great pond-fish. They are small, inexpensive, very hardy and add much color to the pond.

Small to large ponds are fine though the depth should be at least 80 cm (30 in) to avoid freezing. During winter goldfish will become slow, stop eating and often stay on the bottom. This is completely normal and in spring they will become active again. A filter is important to clear waste and keep the pond clean. Plants are essential as they act as part of the filtration system, as well as a food source for the fish. Oxygenating plants are beneficial since they raise oxygen levels.

Compatible fish include rudd, tench, orfe and koi but the latter will require specialised care. Ramshorn snails are helpful by eating any algae that grows in the pond. It is of great importance to introduce fish such as orfe that will consume goldfish eggs in the pond. Without some form of population control, goldfish ponds can easily become overstocked. Koi may also interbreed to produce a sterile new fish.

Wild Goldfish and relationship to Crucian carp

Fancy goldfish are unlikely to survive for long in the wild as they are handicapped by their bright fin colors; however it is not beyond the bounds of possibility that such a fish, especially the more hardy varieties such as the Shubunkin, can survive long enough to breed with its wild cousins. Common and comet goldfish can survive, and even thrive, in any climate in which a pond for them can be created. Introduction of wild goldfish can cause problems for native species. Within three breeding generations the vast majority of the goldfish spawn will have reverted to their natural olive color. Since they are carp, goldfish are also capable of breeding with certain other species of carp and creating hybrid species.

Research by Dr Yoshiichi Matsui suggests that there are subtle differences which demonstrate that while the crucian carp is the ancestor of the goldfish, they are not the same fish.

Behavior

Behavior can vary widely both because goldfish are housed in a variety of environments, and because their behavior can be conditioned by their owners. First and foremost, rumors that goldfish only have a three second memory are completely false. Scientific studies done on the matter have shown that goldfish have strong associative learning abilities, as well as social learning skills. In addition, their strong visual acuity allows them to distinguish between different humans. It is quite possible that owners will notice the fish react favorably to them (swimming to the front of the glass, swimming rapidly around the tank, and going to the surface mouthing for food) while hiding when other people approach the tank. Over time, goldfish should learn to associate their owners and other humans with food, often "begging" for food whenever their owners approach.

Goldfish also display a range of social behaviors. When new fish are introduced to the tank aggressive social behaviors can sometimes be seen, such as chasing the new fish, or fin nipping. These usually stop within a few days. Fish that have been living together are often seen displaying schooling behavior, as well as displaying the same types of feeding behaviors.

Goldfish that have constant visual contact with humans also seem to stop associating them as a threat. After being kept in a tank for several weeks, it becomes possible to "pet" a goldfish on the head, feed it by hand, or even cup a hand around it without it reacting in a frightened manner. Some goldfish have even been trained to swim through mazes, push a ball through a hoop, or swim in a synchronized routine by their owners.

Goldfish have behaviors, both as groups and as individuals that stem from native carp behavior. They demonstrate a high degree of adaptability in feeding, breeding, and evading predators that contribute to a high degree of success in the environment. As fish they can be described as "friendly" towards each other, very rarely will a goldfish harm another goldfish, nor do the males harm the females during breeding. The only real threat that goldfish present to each other is in food competition, commons, comets, and other faster varieties can easily eat all the food during a feeding before fancy varieties can reach it. This can be a problem that leads to stunted growth or possible starvation of fancier varieties when they are kept in a bond with their single-tailed brethren.

Feeding

File:FishesFood.jpg
Common flake fish food

Like most fish, goldfish are opportunistic feeders, meaning they will eat whenever food is available, whether they are hungry or not. This habit can be fatal. Their digestive tract often become so jammed with food that the intestines tear open, killing the fish. Also, an excess of food means more waste and feces, which will pollute the tank. Goldfish need only be fed as much food as they can consume in three to four minutes, and no more than twice a day.

An effective method to determine if your goldfish is being properly fed is to look as their feces. They should be short and chunky, the same color as the food the fish is eating. Long strings of waste that trail behind the fish as they swim could be a sign of over-feeding.

Care has to be taken when choosing the right food for them, because goldfish need less protein (which they cannot digest in excess) and more carbohydrates. However, specialized food for them can be found on the market. Most come in the form of flakes, which float at the top of the aquarium or pellets, which sink slowly to the bottom.

Proper goldfish diet usually consists of a good quality floating pellet type food, along with occasional feedings of peas (removed from their outer skins), blanched green leafy vegetables, and bloodworms. Young goldfish benefit from the addition of brine shrimp to their diet. It is a good idea to set up a feeding ring in there tank where food is always introduced - not only does this prevent food from getting sucked into the filter, but it also ensures the fish know where to go for food. Within a week of its introduction the goldfish should be spending a lot of time at the feeding ring looking for food. Blanched greens should be clipped inside the tank where the goldfish can easily nibble at them.

It is a better idea to introduce blanched greens to the tank than it is to use live plants as a food source. Any plant that can grow fast enough to survive a tank full of voracious goldfish is likely to overrun the tank, creating a maintenance nightmare. On the other hand, tamer plants are likely to be uprooted, or simply torn to shreds, by the efforts of the goldfish.

The oldest living goldfish to date was a goldfish named Goldie, which recently supplanted the previous record holder by living to the age of 45. Goldie was originally won at a fair in Budleigh Salterton, United Kingdom.

Native environment

Goldfish natively live in ponds, and other slow or still moving bodies of water in depths up to 20 m (65 ft). Their native climate is subtropical to tropical and they live in freshwater with a 6.0–8.0 pH, a water hardness of 5.0–19.0 dGH, and a temperature range of 40 to 106 °F (4 to 41 °C) although they will not survive long at the higher temperatures. They are considered ill-suited even to live in a heated tropical fish tank, as they are used to the greater amount of oxygen in unheated tanks, and some believe that the heat burns them. However, goldfish have been observed living for centuries in outdoor ponds in which the temperature often spikes above 86 °F (30 °C). When found in nature, the goldfish are actually an olive green color, and will return to this color if domesticated and then released.

In the wild, the diet consists of crustaceans, insects, and various plant matter.

While it is true that goldfish can survive in a fairly wide temperature range, the optimal range for indoor fish is 68 to 75 °F (20 to 23 °C). Pet goldfish, as with many other fish, will usually eat more food than it needs if given, which can lead to fatal intestinal blockage. They are omnivorous and do best with a wide variety of fresh vegetables and fruit to supplement a flake or pellet diet staple.

Sudden changes in water temperature can be fatal to any fish, including the goldfish. When transferring a store-bought goldfish to a pond or a tank, the temperature in the storage container should be equalized by leaving it in the destination container for at least 20 minutes before releasing the goldfish. In addition, some temperature changes might simply be too great for even the hardy goldfish to adjust to. For example, buying a goldfish in a store, where the water might be 70 °F (approximately 21 °C), and hoping to release it into your garden pond at 40 °F (4 °C) will probably result in the death of the goldfish, even if you use the slow immersion method just described. A goldfish will need a lot more time, perhaps days or weeks, to adjust to such a different temperature.

Because goldfish like to eat live plants, keeping them with plants in an aquarium can be quite a problem. Only a few of the aquarium plant species can survive in a tank with goldfish, for example Cryptocoryne and Anubias species, but they require special attention so that they are not uprooted. Fake plants are often more durable, but the plant branches can often irritate or harm a fish if it comes in contact with them.

Breeding

Goldfish, like all cyprinids, are egg-layers. They produce adhesive eggs that attach to aquatic vegetation. The eggs hatch within 48 to 72 hours, releasing fry large enough to be described as appearing like "an eyelash with two eyeballs". Within a week or so, the fry begin to look more like a goldfish in shape, although it can take as much as a year before they developed a mature goldfish color; until then they are a metallic brown like their wild forebearers. In their first weeks of existence, the fry grow remarkably fast- an adaptation born of the high risk of getting devoured by the adult goldfish (or other fish and insects) in their environment.

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. Dense plants such as Cabomba or Elodea or a spawning mop are used to catch the eggs.

Most goldfish can and will breed if left to themselves, particularly in pond settings. Males chase the females around, bumping and nudging them in order to prompt the females to release her eggs, which the males then fertilize. Due to the strange shapes of some extreme modern bred goldfish, certain types can no longer breed among themselves. In these cases, a method of artificial breeding is used called "hand stripping". This method keeps the breed going, but can be dangerous and harmful to the fish if not done correctly.

Mosquito control

In certain parts of the world, goldfish and other carp are frequently added to stagnant bodies of water in order to reduce the mosquito populations, especially now with the arrival of West Nile Virus which relies on mosquitoes to migrate. Their introduction often had unfortunate consequences for local ecosystems, however.

Aquarium conditions

File:Goldfishies.jpg
Goldfish aquarium

The goldfish is quite hardy, which accounts in part for its popularity. Their supposed reputation in some areas for dying quickly is often due to poor care amongst uninformed buyers looking for a "cheap" pet. The goldfish is usually classified as a coldwater fish, as it 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.

Like most carp, goldfish produce a large amount of waste both in their feces and through their gills, releasing harmful chemicals into the water. This also happens because goldfish cannot digest an excess of proteins, unlike most tropical fish. Build-up of this waste to toxic levels can occur in a relatively short period of time, which is often the cause of a fish's sudden death. Although goldfish were historically displayed in small "goldfish bowls", a healthy and happy average-sized adult goldfish requires at least 10 US gallons (38 L) of water and above in order to live even a small life. In fact, for single-tailed varieties, such as commons or comets, it is really necessary to have 100 gallons (378 L) (for adult fish). Other goldfish experts say that it is the amount of water surface area, not the water volume, that decides how many goldfish may live in a container; one square foot of water surface area for every inch of goldfish length (370 cm²/cm). For example, if you had three goldfish of length 4 inches (10 cm) each, you might need 12 square feet (1,080 cm²) of water surface area. Surface area is an approximate measure of how much oxygen may be absorbed into the water from the air. If the water is being further aerated by way of water pump, filter or fountain, more goldfish may be kept in the container.

A frequent misconception is that airstones do not increase the amount of dissolved oxygen in the water. Most of the transfer of oxygen occurs when the bubbles are formed at and around the airstone, and therefore airstones that create smaller bubbles in large amounts are preferred over those creating fewer larger bubbles. The ripples they create at the surface of the water also increase the surface area and therefore facilitate oxygen exchange at the surface of the tank. For the beginner acquiring a goldfish, the best advice that can be given is to get a 40 gallon long tank, these are typically inexpensive, have a huge surface area, and will be a suitable fish home for over 2 years. Beginner filtration can simply be provided by a box filter hung over the back of the tank, though filtration should be rated for 60+ gallons (227 L), as the ammonia levels produced by goldfish are much higher than those produced by the tropical fish filters are typically rated for. It is also imperative that adequate biological filtration is provided, as the breakdown of nitrates occurs much more slowly at the colder temperatures goldfish are kept at. One useful compromise is to keep the aquarium heated to a constant 72° F (22°C), as this temperature keeps the fish active while at the same time aiding bacterial growth.

In the end, it may be easier to transfer the goldfish to a pond rather than to a 100 gallon tank (378 L), as few homes can support the size. This is an area where most serious aquaculturists will agree, ponds are superior to tanks in the long run for goldfish.

Aquariums

Despite the small size of goldfish, baby fry grow very quickly. Therefore, a goldfish pond or a massive tank often more of an investment than typically expected. Inexpensive ways to keep goldfish in more humane conditions until such an environment can be arranged into constructing an emergency home for them out of large plastic or glass containers, which can be as simple as 20 to 40 gallon (76-151 L) plastic boxes. These containers will house a fish much better than a small bowl, though proper hygiene must still be maintaied. A 20% change of the water twice a week and using an aquarium vacuum to clean any dropping off of the bottom are effective methods in preserving water clarity. Additional rocks and plants in the tank help to remove nitrates from the water and also keep the fish entertained. A more ideal eventual solution is a 100 to 200 gallon long tank, and while this may seem excessive, common goldfish can grow to a foot (30.5 cm) long and may require such a large tank to have enough room to swim. Goldfish kept in smaller tanks will have much shorter lifespans.

Starting filtration should be provided by a box filter that hangs on the back of the tank. Undergravel filters have their uses, but they are inappropriate in a goldfish tank as they will quickly clog with detrious. Another excellent argument against undergravel filters is that the beneficial bacteria can sometimes die off, yet the filter will still appear to be working. The resulting spike in ammonia is often enough to kill every fish in the tank. Canister filters are another excellent choice, but usually well outside the budget of a beginning aquaculturist. Wet-dry and protein skimmer options are usually reserved for marine aquariums, so it would be extreme overkill to use them here. Simply put, the best option is to purchase a box filter rated for twice the volume of your tank, as goldfish produce copious amounts of waste due to their large size. An external box filter is preferable.

Lighting is the one area where someone on a budget can avoid investing money initially. Goldfish need day and night cycles to be healthy, but for tanks under 30 gallons (113 L) the room lights will be sufficient, at least temporarily. Another excellent area to save money is on the full hoods often sold at a great cost than the tanks themselves at the pet store. A much more economical cover for the tank can be constructed out of the plastic mesh backing used for making loop-and-stitch rugs. This can be easily found at any craft store, and can be cut to fit the filters for your tank. Suitable covers can also be constructed out of particle board, which can be found at any hardware store. However, if a source of natural light is available (eg. a window), the fish will be much happier than if they were under artificial lighting.

One last point that should be made for beginning goldfish owners is on the use of a heater. Goldfish may be coldwater fish, but this does not mean they can tolerate rapid changes in temperature. The sudden shift in temperature the comes at night, for example in an office building where a goldfish might be kept in a small office tank, could do them in, especially in winter. Therefore, even for cold water fish under certain circumstances, it is recommended that a tank heater be set to 68-72º F (20-22° C) and left in the tank year round. This is especially important for fancy varieties of goldfish, as they are less hardy than their brethren. Bear in mind, however, that temperatures over 25 degrees C can be extremely damaging for goldfish (this is the main reason why they shouldn't be kept in tropical tanks). As long as the room temperature does not fluctuate massively or drop extremely low, a heater can be left out of the aquarium.

As a footnote on tank sizes, a couple of very small goldfish will be fine in a 10-15 gallon (38-57 L) aquarium for a couple of months (with good filtration and water changes twice weekly). Beyond this time, however, the owner begins to run the risk of stunting their fish. A 40-50 gallon aquarium would suit 4 fish for a couple of years, however, in the end, a 100 gallon tank (or larger) needs to be obtained in order to suit the needs of the fishes.

There is a consumer stereotype that goldfish can be kept in small bowls. Unfortunately, the risk of stunting, deoxygenation, ammonia/nitrite poisoning caused by such a small environment means that this is hardly a suitable home for a gold, let alone any fish. It is truly funny and sad when somebody says that their fish 'lived for 4 years in a bowl and grew to a whopping 3 inches!' (7.5 cm) Most goldfish don't make it past a week in these unsuitable environments. Even among otherwise excellent aquarists, there is still an opinion that it is acceptable to keep these fish in small (under 50 gallons) tanks. Perhaps these people have never seen a full-sized goldfish, and this is not surprising, considering the fate that most golds suffer.

Care

There exists a great deal of conflicting information on the best way to care for a goldfish, or rather, on the best feasible ways to care for one. The best solution is to build an indoor pond, as this would provide the benefits of an outdoor pond without the risk presented by raccoons, kingfishers, children, and weather. As for indoor care, there are a few general tips that should be noted.

  • A quality mechanical filtration system rated for at least twice the volume of your tank is optimal for most tanks. Goldfish produce copious amounts of waste, and this factor must be constantly dealt with to prevent ammonia spikes.
  • Undergravel filtration is usually not recommended for most goldfish tanks. These systems require up to six months to establish, and goldfish produce far too much waste. The filter plate will clog with detrious and become useless within a matter of weeks. Not only that, but these systems are only effective in tanks under 40 gallons, while most goldfish pairs or trios require 55 gallon tanks by the time they are fully grown.
  • Floating pellets (particularly floating pond pellets) are one of the best staple foods for fish. Uneaten food can be removed easily, and the fish have no trouble finding the food before it dissolves.
  • A twenty gallon long tank is usually a good choice for starting fishkeepers. While most will eventually have to upgrade to fifty gallon tanks, it is best for a beginner to have a tank that doesn't create additional problems. Larger tanks require more planning, more initial investment, and more mechanical inclination in setting it against the right walls and floor joists of the home. It is also nice in the long run to have the twenty gallon tank to use in case of emergency (such as a bigger tank breaking) or as a hospital/quarantine tank.
  • An excellent idea when moving from a smaller (10-20 gallon) to a medium (37-55 gallon) tank is to use your old filter, and add an additional identical unit on the opposite end of the tank. It is nice to plan your filter so that when you move to a larger tank the filter can handle it as well. Two medium size mechanical filters working in conjunction will do wonders for your water quality, as well as ensure that if a filter were to break, there is at least some filtration until a replacement can be obtained.
  • Air pumps are becoming outdated for most standard filtration setups. Air-driven mechanical filters are simply not powerful enough to deal with larger tanks, and should be reserved for fry tanks. The noise of most air pumps is also annoying. Most decorations driven by these air pumps do little to improve the oxygenation of the water. Another simple argument against the air pump is that it does not deal with the problem of tank overcrowding - if fish are gasping for air (lack of dissolved oxygen) is it almost always better to remove fish from the tank rather than resort to gimmicks to try and increase the air. You never want your fishes lives to depend on an electrical device being able to run constantly, as in the event of a failure their lives would be endangered.
  • Lastly, keep the tank cold. Goldfish cannot be mixed with tropical fish, and indeed it is not even a good idea to mix them with other fish. Most catfish (ie plecos) that can be kept in coldwater get too big to keep in the tank, and they are a danger to the goldfish. Numerous accounts can be found of cases where a goldfish was injured, and a catfish will take a liking to sucking on the wounds. There are also a few stories of celestial goldfishes eyeballs being sucked out by a wandering algae eater. The bottom line, don't mix.

Edibility and cruelty

Although edible, the goldfish is rarely eaten. A fad among American college students for many years was swallowing goldfish as a stunt and as an initiation process for fraternities. 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 no longer continued.

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 this has since been watered down to only prevent goldfish being given as prizes to unaccompanied minors. However, in Rome, Italy, the city passed a law in late 2005, which banned the use of goldfish or other animals as carnival prizes. Rome has also banned the keeping of goldfish in "goldfish bowls", on the premise that it's cruel to the fish to live in such a small, confined space.

File:Goldfish in bowl.jpg
Goldfish in a goldfish bowl

Killing fish humanely for human consumption or benign purposes (such as putting down an ill fish) is still legal in most countries (provided that the fish is not a protected fish caught in the wild, a fish in protected reserves or in water where the person concerned has no right to collect the fish). In the United Kingdom, it is illegal to sell live fish (including goldfish) as "feeder fish" for consumption by other animals.

See also

Notes

  1. Les Pearce. ""Common Gold Fish"". Aquarticles. Retrieved 20 June. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)

References

External links

A distorted view of a goldfish in a goldfish bowl.
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