Taxonomic name: Carassius auratus (Linnaeus, 1758)
Synonyms: Carassius auratus auratus (Linnaeus, 1758), Carassius auratus cantonensis (Tchang, 1933), Carassius carassius auratus (Linnaeus, 1758), Carassius chinensis (Gronow, 1854), Carassius encobia (Bonaparte, 1845), Carassius gibelioides (non Cantor, 1842), Cyprinus auratus (Linnaeus, 1758), Cyprinus langsdorfi (Cuvier & Valenciennes, 1842), Cyprinus maillardi (Guichenot, 1863), Cyprinus mauritianus (Bennett, 1832), Cyprinus thoracatus (Valenciennes, 1842), Leuciscus auratus (Mauduyt, 1849-51)
Common names: aranyhal (Hungarian-Hungary), caras rosu (Romanian), caras-auriu (Romanian), carassin doré (French), carassio dorato (Italian), carpa dorada (Spanish-Mexico), cheisopsaro (Greek), chernyi teleskop (Russian), chrysopsaro (Greek), chryssopsaro (Greek), ciprino dorato (Italian), cyprin doré (French), dorade de Chine (French), edible goldfish (English-Malaysia), funa (Hawaiian), gibel carp (English-Kazakhstan), gold crucian carp (English-Taiwan), golden carp (English-Australia), Goldfisch (German), goldfish (English), goudvis (Dutch-Netherlands), Goudvis (Afrikaans-South Africa), Guldfisk (Swedish-Sweden), guldfisk (Danish), gullfisk (Norwegian), I'a'ula'ula (Hawaiian), ikan mas (Malay), kam tsak (Cantonese-Hong Kong), kam ue (Cantonese-Hong Kong), kapr zlatý (Czech), kaprík zlatý (Czech), karas (Russian-Ukraine), karas cinsky (Czech), karas stríbritý (Czech), karas stribrity vychodoasijsky (Czech), karas vetší (Czech), karas zlatý (Slovak), karas zlocisty (Polish), karas zlocisty a. chinski (Polish), karuss (Norwegian), kin-buna (Japanese), kirmizi balik (Turkish), kultakala (Finnish), mahi-e-hoz (Farsi-Iran), native carp (English-Australia), ngan tsak (Cantonese-Hong Kong), peixe dourado (Portuguese), peixe encarnado (Portuguese), peixe-dourado (Portuguese), pesce dorato (Italian-Italy), pesco rosso (Italian-Switzerland), peshk i kuq (Albanian-Albania), pez dorado (Spanish-Mexico), pez rojo (Spanish-Spain), pimpão (Portuguese-Portugal), poisson rouge (French), serebryanyi karas' (Russian-Russian Fed), sølvkaruds (Danish), sølvkarusse (Danish), tawes (Tagalog-Philippines), tsak ue (Cantonese-Hong Kong), zlatnakarracuda (Bulgarian), zolotaja rybka (Russian-Belarus)
Organism type: fish
Native to Asia, goldfish (Carassius auratus) have been introduced worldwide due to their popularity as pond and aquarium fish. Releases, both intentional and unintentional, have meant that this species has formed wild populations in many new locations. Concerns have been raised about the impacts that goldfish have on the aquatic community, including increasing turbidity, predation upon native fish, and helping to facilitate algal blooms.
A small to moderately-sized fish with a deep body and rounded cross-section. Large head and eyes with a small mouth and a forked tail. Scales are large and the single dorsal fin has 3-4 stout spines at the leading edge. Colour ranges from olive-bronze to deep golden along dorsal surface, fading to silvery-white along the belly (McDowall, 2000). May grow up to 41cm in length, 2kg in weight and live for 30 years in captivity (FishBase, 2004).
lakes, water courses, wetlands
Rivers, lakes, ponds, lagoons and ditches with cold, slow-flowing water and aquatic vegetation (FishBase, 2004). Able to withstand prolonged exposure to salinities above 15 ppt (FishBase, 2004) and can tolerate low levels of dissolved oxygen (McDowall, 2000).
The passage of cyanobacteria through the goldfish intestine stimulates cyanobacterial growth, which may result in algal blooms occurring. The bottom-sucking feeding methods of goldfish can also contribute towards algal blooms by re-suspending nutrients, which makes them available to algae (Morgan & Beatty, 2004). Goldfish have also been known to prey upon the eggs, larvae and adult of native fishes (Morgan & Beatty, 2004), as well as increasing water turbidity and depleting aquatic vegetation (Richardson et al., 1995).
Valued as an ornamental pond and aquarium fish. Used in scientific experiments (FishBase, 2004).
Many different varities of goldfish have been produced, through selective breeding for a wide variety of colours and fin shapes. These fish usually revert to olive-bronze wild colouration and normal fin shapes if released from captivity (McDowall, 2000).
Native range: Native to central Asia, China and Japan.
Known introduced range: Introduced worldwide as a pond and aquarium species (FishBase, 2004).
Introduction pathways to new locations
For ornamental purposes: Often introduced to outdoor ponds as an ornamental fish.
Pet/aquarium trade: Introduced worlwide as aquarium fish.
Local dispersal methods
Escape from confinement: Wild populations have often been established by released pet goldfish.
For ornamental purposes (local): Often introduced to outdoor ponds as an ornamental fish.
Intentional release: Goldfish have been introduced by acclimatisation societies to some countries.
Intentional release: Goldfish have been introduced by acclimatisation societies to many localities.
Preventative measures: The use of potentially invasive alien species for aquaculture and their accidental release/or escape can have negative impacts on native biodiversity and ecosystems. Hewitt et al, (2006) Alien Species in Aquaculture: Considerations for responsible use aims to first provide decision makers and managers with information on the existing international and regional regulations that address the use of alien species in aquaculture, either directly or indirectly; and three examples of national responses to this issue (Australia, New Zealand and Chile). The publication also provides recommendations for a ‘simple’ set of guidelines and principles for developing countries that can be applied at a regional or domestic level for the responsible management of Alien Species use in aquaculture development. These guidelines focus primarily on marine systems, however may equally be applied to freshwater.
Copp et al, (2005) Risk identification and assessment of non-native freshwater fishes presents a conceptual risk assessment approach for freshwater fish species that addresses the first two elements (hazard identification, hazard assessment) of the UK environmental risk strategy. The paper presents a few worked examples of assessments on species to facilitate discussion. The electronic Decision-support tools- Invasive-species identification tool kits that includes a freshwater and marine fish invasives scoring kit are made available on the Cefas (Centre for Environment, Fisheries & Aquaculture Science) page for free download (subject to Crown Copyright (2007-2008)).
Physical: Gill nets, seine nets and electrofishing can be used to control goldfish populations (Morgan & Beatty, 2004).
Eats a variety of aquatic plants (including algae), detritus, crustaceans, worms, small insects and snails (FishBase, 2004; McDowall, 2000).
Spawning occurs in shallow water amongst weeds, and up to several hundred thousand small eggs (1-2mm diameter) are laid at once (McDowall, 2000). Individual fish can spawn 3-10 lots of eggs at intervals of 8-10 days. Cold water during winter is essential for proper ova development (FishBase, 2004).
Eggs hatch in around a week. Young attach to aquatic plants for several days while yolk sac is absorbed (McDowall, 2000).
Reviewed by: Dr. David Rowe, NIWA (National Institute of Water & Atmospheric Research). Hamilton New Zealand.
Principal sources: McDowall, R. M. 2000. The Reed field guide to New Zealand freshwater fishes. Auckland, Reed.
FishBase, 2004. Species profile Carassius auratus
Compiled by: IUCN SSC Invasive Species Specialist Group
Updates with support from the Overseas Territories Environmental Programme (OTEP) project XOT603, a joint project with the Cayman Islands Government - Department of Environment
Last Modified: Monday, 4 October 2010