Goldfish
Carassius auratus
Vectors of spread:
ID Characteristics
Size: Goldfish typically grow to 12 – 22 cm. However, Goldfish are only limited by their environment; once in a pond or lake, a much more varied and abundant diet is available to them, allowing them to grow and thrive.
Colour: Bright orange to olive green or creamy white. Wild populations are typically olive to gray.
Fins:
- Long dorsal fin with 15 – 21 rays and a hard serrate spine
- Complete lateral fin, with 25 – 31 scales in lateral series
- Concave anal fin on the male, but convex on the female
- Deeply-forked tail
Similar Species
There are several native and non-native species of minnows and carps (Cyrinidae) that occur in BC.
Goldfish are distinguished from all other Cyprinidae by their dorsal fin which is longer than their head, and the presence of a stiff, serrate spine at the origin of the dorsal and anal fins.
Invasive: Goldfish are sometimes confused with, and often referred to as Koi. Both species are invasive, and are likely to have similar impacts. You can tell them apart by looking at the lower lip – Goldfish lack barbels (whisker-like projections) that are present in Koi.
Scroll down to the bottom of the species profile page for more Koi images.
Koi have barbels, whereas Goldfish don’t (Photo credit: Stan Shebs, Wikipedia)
Report
Please report any sighting of Goldfish by clicking here.
Habitat and Origin
Origin: Goldfish are originally from Eastern Asia, including parts of China, Hong Kong, Japan and Korea. They are a common pet, and have unfortunately been released, or escaped into some waterbodies in BC.
Habitat: Goldfish prefer areas where there is submerged vegetation; preferred habitats include streams and pools, ditches, and ponds. They can tolerate a wide range of temperatures and oxygen levels, and are unaffected by ice cover.
Lifespan and Reproduction
Goldfish usually have a lifespan of 6 – 7 years, but a maximum of 30 years has been recorded.
Goldfish are rapid and prolific reproducers. Spawning occurs in shallow water amongst weeds, and up to several hundred thousand eggs are laid at once. Individual goldfish can spawn 3 – 10 lots of eggs at intervals of 8 – 10 days.
Current Distribution
Propagation and Vectors of Spread
Goldfish have been intentionally released into BC water bodies by pet owners. In other cases, they have escaped from outdoor ponds and aquariums. Once introduced, they can easily become established and spread easily to connected water bodies.
Ecological Impacts
- Goldfish have been reported to compete with, and even prey upon native fish species in areas where they have been introduced.
- They can disturb sediment while feeding, which increases water turbidity and may harm aquatic plants.
- Goldfish can carry diseases such as koi herpesvirus that can harm local fish populations.
- Goldfish are extremely resistant, and will adapt to a wide range of water temperatures and oxygen levels, as well as a number of food sources with low protein requirements.
What Can I Do?
Goldfish have been have been observed in at least 6 water bodies in the Sea to Sky region. PREVENTION of further spread and new introductions is key.
Under s10 of the federal Aquatic Invasive Species Regulation, it is prohibited to introduce an aquatic species into a region or body of water frequented by fish where it is not indigenous unless authorized to do so under federal or provincial law. This includes moving aquatic species from the pet/aquarium or food trade into natural waters.
Learn to identify Goldfish: use the images presented in this profile page.
What to do if you spot it: You can report any Goldfish sighting by clicking here.
Don’t Let It Loose. Through public education and awareness, encourage pet owners to consider re-homing services and rescue centers for unwanted aquarium fish or euthanasia as a last resort. Re-homing services in the Sea to Sky include:
Never use Goldfish as live bait.
If you catch Goldfish:
- The BC Freshwater Fishing Regulations outline when and how you are permitted to fish with a Recreational Fishing License. These regulations vary by region and waterbody and are in place to protect native fish populations and sensitive aquatic habitats.
- Any fishing or capture method beyond what is permitted by a Recreational Fishing License requires a provincial Scientific Collection Permit.
- In waterbodies where a species quota is not specified the species may be retained, unless general regulations are in place that prevent retention (e.g., release all fish).
- Call the Conservation Officers (1-877-952-7277)
Control
Mechanical Control: Mechanical methods of controlling Goldfish are only likely to achieve population suppression, not eradication.
Population suppression efforts, however, may help reduce biomass, and hence lessen negative impacts. Mechanical removal methods may include hook & line fishing, gill-netting and electrofishing with scoop netting. In the right conditions, repeated electrofishing & scoop netting can remove some of the mature Goldfish from the water body, however the fish tend to swim deep, or into vegetation, or mud to evade the electrofisher, so it is very difficult to shock and remove all fish present.
Another option, if possible, is to drain a water body completely and allow the lake bottom to freeze completely over winter. The success of this method is not well-documented, and would be dependent on very cold winter temps and very low oxygen levels in the sediment.
Most mechanical control methods require permits, contact SSISC for more information.
Chemical Control: The temporary application of a piscicide (e.g., rotenone) to a water body has achieved successful eradication of invasive fish in other regions of BC. This method requires restocking of the water body with native fish following the piscicide treatment, since the pesticide affects all gill-breathing organisms.
However, there is a lengthy permitting and approval process required to carry out this type of control. There are no plans to use this method in the Sea to Sky region, at this time.
Biological Control: Natural predators like birds of prey don’t seem to eat Goldfish at a level that would suppress the population, so population control is currently unlikely.
References
- Government of British Columbia, Goldfish Invasive Species Alert Factsheet, https://www2.gov.bc.ca/assets/gov/environment/plants-animals-and-ecosystems/invasive-species/alerts/goldfish_alert.pdf
- Government of Ontario, Goldfish, https://www.ontario.ca/page/goldfish
- Invasive Species Compendium, Carassius auratus auratus (Goldfish), https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.90562
- Ministry of Forests, Lands, Natural Resources Operations & Rural Development Contacts, personal communication with Andrew Klassen
- Resort Municipality of Whistler, personal conversations
- Thompson Rivers University, personal communication with Brian Hiese
Goldfish Images
Similar Invasive Fish: Koi
Koi are another, similar looking, invasive fish species that have been observed in local lakes and poinds, likely from being intentionally introduced. If you see them, be sure to report your sighting.
