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Carassius auratus

What do they look like?

As there are over a hundred varieties of goldfish, coloration and physical characteristics vary greatly. The common goldfish has two sets of paired fins - the pectoral fins and pelvic fins, and three single fins- the dorsal, caudal, and anal fin. The head lacks scales. Goldfish have very large eyes and acute senses of smell and hearing. Instead of true teeth, goldfish have teeth in their throats which they use to crush food.

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    3.0 (high) kg
    6.61 (high) lb
  • Range length
    41.0 (high) cm
    16.14 (high) in

Where do they live?

Although goldfishes originated in China, they have now spread worldwide in aquariums, ornamental pools, and into the wild.

What kind of habitat do they need?

In the wild, goldfish can be found in slow-moving, freshwater bodies of water. As with their close relative the carp, they thrive in slightly murky water. In captivity, an aquarium with live plants and a dirt bottom is ideal. Bi-weekly water changes are a good idea as a goldfish tank is hard to keep clean. Live plants must be replaced fairly regularly; goldfish enjoy eating them. Small pebbles are a suitable substitute for the pond-like bottom. Typically, goldfish will survive in water temperatures ranging from freezing to 30 degrees centegrade. Goldfish prefer a pH range of 6.5-8.5.

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

How long do they live?

Although there is one report of a pet goldfish who lived 43 years, 25 years is a more reasonable maximum lifespan for a goldfish kept in a pond. In an aquarium, ten years is more likely. In the wild, lifespan is undoubtedly less.

How do they behave?

In the wild, goldfish often travel in schools. They are not particularly aggressive fish.

How do they communicate with each other?

What do they eat?

In the wild, goldfish are omnivores. They eat plants, insects such as mosquito larvae, small crustaceans, zooplankton, and detritus (dead plant and animal matter found on the bottom).

In captivity, goldfish are commonly fed dried flake or pellet food. Good diet supplements include freeze dried Tubifex worms, mosquito larva, bloodworms, daphnia, brineshrimp, and vegetation such as boiled peas and lettuce.

What eats them and how do they avoid being eaten?

Just about anything that eats fish would eat goldfish.

Do they cause problems?

Introduced populations are due primarily to people releasing their pets into local waterways. Goldfish should not be released into ponds in the wild because they breed quickly and are capable of crowding out native fish species. They are considered pests in most places where they have been introduced.

How do they interact with us?

Goldfish farming has become an industry of notable size. Millions of fish are bred each year and sold to aquarium shops for resale to fish enthusiasts. In North America there is a demand for goldfish to be used as bait by anglers. Pet shops often have feeder goldfish to sell to owners of carnivorous aquarium fish.

  • Ways that people benefit from these animals:
  • pet trade

Are they endangered?

Goldfish are quite abundant.

Some more information...

Goldfish and common carp can hybridize.

Contributors

Robin Street (author), University of Michigan-Ann Arbor.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

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Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

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Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

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Neotropical

living in the southern part of the New World. In other words, Central and South America.

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Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

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bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

fertilization

union of egg and spermatozoan

freshwater

mainly lives in water that is not salty.

herbivore

An animal that eats mainly plants or parts of plants.

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

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oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

References

A Fishkeeper's Guide to Fancy Goldfishes; Dr. Chris Andrews; Tetra Press; 1987.

The Audubon Society Field Guide to North American Fishes, Whales and Dolphins; 1993.

Froese, R., D. Pauly, eds.. 2002. "Species summary: Carrasius auratus" (On-line). Accessed 3 April 2002 at http://www.fishbase.org.

 
University of Michigan Museum of ZoologyNational Science Foundation

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Street, R. 2002. "Carassius auratus" (On-line), Animal Diversity Web. Accessed April 21, 2014 at http://www.biokids.umich.edu/accounts/Carassius_auratus/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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