Scientific classificationedit
Kingdom:
Animalia
Phylum:
Chordata
Class:
Actinopterygii
Order:
Cypriniformes
Family:
Cyprinidae
Subfamily:
Cyprininae
Genus:
Carassius
Species:
C.auratus
Koi and common carp may also interbreed with goldfish to produce sterile hybrids. C. Taxonomy
There has been considerable debate about the taxonomy of the goldfish. C. auratus have a more pointed snout, while the snout of C. gibelio often has a grayish/greenish color, while crucian carp are always golden bronze. C. auratus are differentiated from other Carassius species by several characteristics. auratus have fewer than 31 scales along the lateral line, while crucian carp have 33 scales or more.
In outdoor ponds, and in the wild, goldfish can grow to about 14 inches (36 cm).[16]
As of April 2008, the largest goldfish in the world was believed by the BBC to measure 19 inches (48 cm), in the Netherlands.[17] At the time, a goldfish named "Goldie", kept as a pet in a tank in Folkestone, England, was measured as 15 inches (38 cm) and over 2 pounds (0.91 kg), and named as the second largest in the world behind the Netherlands fish.[17] The secretary of the Federation of British Aquatic Societies (FBAS) stated of Goldie's size, "I would think there are probably a few bigger goldfish that people don't think of as record holders, perhaps in ornamental lakes".[17] In July 2010, a goldfish measuring 16 inches (41 cm) and 5 pounds (2.3 kg) was caught in a pond in Poole, England, thought to have been abandoned there after outgrowing a tank.[18] On November 16, 2020, a 15 inch (38.1 cm) 9 pound (4.1 kg) goldfish was found in a 16-acre (6.5 ha) lake in Greenville, South Carolina, while conducting a population survey of Oak Grove Lake.[19]
Vision
Goldfish have one of the most studied senses of vision in fishes.[20] Goldfish have four kinds of cone cells, which are respectively sensitive to different colors: red, green, blue and ultraviolet. Size
When kept in small indoor aquariums, goldfish tend to stay about 1 inch (2.5 cm) to 2 inches (5.1 cm) long. The ability to distinguish between four different primary colors classifies them as tetrachromats.[21]
Hearing
Goldfish have one of the most studied senses of hearing in fish.[22] They have two otoliths, permitting the detection of sound particle motion, and Weberian ossicles connecting the swimbladder to the otoliths, facilitating the detection of sound pressure.[23]. Goldfish may grow larger if moved to bigger fish tanks, but they usually do not grow longer than 6 inches (15 cm).
In their first weeks of life, the fry grow quickly—an adaptation born of the high risk of getting devoured by the adult goldfish (or other fish and insects) in their environment.[24]
Some highly selectively bred goldfish can no longer breed naturally due to their altered shape. In captivity, adults may also eat young that they encounter.
Breeding goldfish by the hobbyist is the process of selecting adult fish to reproduce, allowing them to reproduce and then raising the resulting offspring while continually removing fish that do not approach the desired pedigree.[25]. Goldfish can only grow to sexual maturity with enough water and the right nutrition. Most goldfish breed in captivity, particularly in pond settings. Their eggs are adhesive and attach to aquatic vegetation, typically dense plants such as Cabomba or Elodea or a spawning mop. The artificial breeding method called "hand stripping" can assist nature, but can harm the fish if not done correctly. The eggs hatch within 48 to 72 hours.
Within a week or so, the fry begins to assume its final shape, although a year may pass before they develop a mature goldfish color; until then they are a metallic brown like their wild ancestors. Breeding usually happens after a significant temperature change, often in spring. Males chase gravid
female goldfish (females carrying eggs), and prompt them to release their eggs by bumping and nudging them.
Goldfish, like all cyprinids, are egg-layers.
Survival is shorter under higher temperatures, suggesting that this is a cold weather adaptation. Researchers speculate that this is specifically an adaptation to survival in frozen water bodies over winter.
Energy is obtained from liver glycogen. Respiration
Goldfish are able to survive short periods of entirely anoxic conditions. This process depends upon a pyruvate decarboxylase - the first known in vertebrates.[26][27]
Salinity
Although they are a freshwater fish, goldfish have been found in brackish water with a salinity of 17.[28].
Behaviours ;
Goldfish are gregarious, displaying schooling behavior, as well as displaying the same types of feeding behaviors. Commons, comets, and other faster varieties can easily eat all the food during a feeding before fancy varieties can reach it. After being kept in a tank for several weeks, sometimes months, it becomes possible to feed a goldfish by hand without it shying away.
Goldfish have a memory-span of at least three months and can distinguish between different shapes, colors, and sounds.[29][30] By using positive reinforcement, goldfish can be trained to recognize and to react to light signals of different colors[31] or to perform tricks.[32] Fish respond to certain colors most evidently in relation to feeding.[citation needed] Fish learn to anticipate feedings provided they occur at around the same time every day. They are a generalist species with varied feeding, breeding, and predator avoidance behaviors that contribute to their success. The only real threat that goldfish present to each other is competing for food. Goldfish may display similar behaviors when responding to their reflections in a mirror.[citation needed]
Goldfish have learned behaviors, both as groups and as individuals, that stem from native carp behavior. Over time, goldfish learn to associate their owners and other humans with food, often "begging" for food whenever their owners approach.[citation needed]
Goldfish that have constant visual contact with humans also stop considering them to be a threat. Very rarely does a goldfish harm another goldfish, nor do the males harm the females during breeding. As a result, care should be taken to combine only breeds with similar body type and swim characteristics.
Cognitive abilities
Goldfish have strong associative learning abilities, as well as social learning skills. As fish, they can be described as "friendly" towards each other. In addition, their visual acuity allows them to distinguish between individual humans. Owners may notice that 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. This can lead to stunted growth or possible starvation of fancier varieties when they are kept in a pond with their single-tailed brethren
Cultivation in aquarium ;
However, higher temperatures may help fight protozoan infestations by accelerating the parasite's life-cycle—thus eliminating it more quickly. 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.[citation needed]
Because goldfish eat live plants, their presence in a planted aquarium can be problematic. Active aeration by way of a water pump, filter or fountain effectively increases the surface area.[citation needed]
The goldfish is classified as a coldwater fish, and can live in unheated aquaria at a temperature comfortable for humans. The water surface area determines how much oxygen diffuses and dissolves into the water. Care must also be taken when adding water, as the new water may be of a different temperature. Fancy goldfish (which are smaller) should have about 10 US gallons (38 l; 8.3 imp gal) per goldfish. 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. Fish have cells called chromatophores that produce pigments which reflect light, and give the fish coloration. Temperatures under about 10 °C (50 °F) are dangerous to fancy varieties, though commons and comets can survive slightly lower temperatures. However, goldfish respond to people by surfacing at feeding time, and can be trained or acclimated to taking pellets or flakes from human fingers. 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. Plastic plants are more durable.[citation needed]. 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. For common and comet varieties, each goldfish should have about 20 US gallons (76 l; 17 imp gal) of water. A general rule is have 1 square foot (0.093 m2). The reputation of goldfish dying quickly is often due to poor care.[42] The lifespan of goldfish in captivity can extend beyond 10 years.[43]
If left in the dark for a period of time, goldfish gradually change color until they are almost gray.[citation needed] Goldfish produce pigment in response to light, similarly to how human skin becomes tanned in the sun. 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. Extremely high temperatures (over 30 °C (86 °F)) can also harm goldfish. The optimum temperature for goldfish is between 20 °C (68 °F) and 22 °C (72 °F).[41]
Like all fish, goldfish do not like to be petted. In aquaria
Like most species in the carp family, goldfish produce a large amount of waste both in their feces and through their gills, releasing harmful chemicals into the water.
In frosty climes, the depth should be at least 80 centimeters (31 in) to preclude freezing. Moor, veiltail, oranda and lionhead can be kept safely in outdoor ponds year-round only in more tropical climates and only in summer elsewhere.
Compatible fish include rudd, tench, orfe and koi, but the last require specialized care. Without some form of animal population control, goldfish ponds can easily become overstocked. This is normal; they become active again in the spring. Ramshorn snails are helpful by eating any algae that grows in the pond. Plants are essential as they act as part of the filtration system, as well as a food source for the fish. Plants are further beneficial since they raise oxygen levels in the water.
Like their wild ancestors, common and comet goldfish as well as shubunkin can survive, and even thrive, in any climate that can support a pond, whereas fancy goldfish are unlikely to survive in the wild as their bright colors and long fins make them easy prey. Common, London and Bristol shubunkins, jikin, wakin, comet and some hardier fantail goldfish can be kept in a pond all year round in temperate and subtropical climates. Unless the pond is large enough to maintain its own ecosystem without interference from humans, a filter is important to clear waste and keep the pond clean. During winter, goldfish become sluggish, stop eating and often stay on the bottom of the pond. Goldfish are popular pond fish, since they are small, inexpensive, colorful and very hardy. Fish such as orfe consume goldfish eggs.
Ponds small and large are fine in warmer areas (although it ought to be noted that goldfish can "overheat" in small volumes of water in the summer in tropical climates). In an outdoor pond or water garden, they may even survive for brief periods if ice forms on the surface, as long as there is enough oxygen remaining in the water and the pond does not freeze solid.
Overfeeding can be deleterious to their health, typically by blocking the intestines. However, introducing goldfish has often had negative consequences for local ecosystems.[44]
Market
The market for live goldfish and other crucian carp usually imported from China was $1.2 million in 2018. When excess food is available, they produce more waste and feces, partly due to incomplete protein digestion. Overfeeding can sometimes be diagnosed by observing feces trailing from the fish's cloaca.
Goldfish-specific food has less protein and more carbohydrate than conventional fish food. As with all animals, goldfish preferences vary.
For mosquito control
Like some other popular aquarium fish, such as the guppy, goldfish and other carp are frequently added to stagnant bodies of water to reduce mosquito populations. They are used to prevent the spread of West Nile virus, which relies on mosquitoes to migrate. This happens most often with selectively bred goldfish, which have a convoluted intestinal tract. Enthusiasts may supplement this diet with shelled peas (with outer skins removed), blanched green leafy vegetables, and bloodworms. In the wild, the diet of goldfish consists of crustaceans, insects, and various plant matter. Some high quality varieties cost between $125 to $300.[45]. Young goldfish benefit from the addition of brine shrimp to their diet. Like most fish, they are opportunistic feeders and do not stop eating on their own accord.
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