Carassius auratus

The goldfish is a domesticated freshwater fish descended from a carp native to eastern Asia. Long valued for their color and beauty, they have been kept as ornamental pond fish for at least a thousand years in China. Today, they are bred for the familiar gold color (the typical common goldfish) or for other colors and features (long fins or large eyes). Goldfish are hardy and grow quickly. They can live up to 30 years in captivity, reaching 5 pounds and over a foot long. They tolerate a wide range of water temperatures and even brackish or mildly saline water. They are omnivorous, eating algae, worms, plants, snails and small insects, and the eggs and young of other fish.

Did You Know?

Goldfish can live up to 30 years in captivity, reaching 5 pounds and over a foot long.


Does the harvest for wildlife trade or captive breeding of this species harm wild populations?

Little Cause for Concern

Goldfish are almost exclusively bred in captivity so the pet trade does not threaten the survival of wild populations.

EcoHealthy Recommendation:

Only acquire a pet that is from a reputable breeder or dealer.

Invasion Threat

Does the release or escape of this species into the wild harm the environment and/or economy?

Significant Cause for Concern

Goldfish have established self-sustaining populations outside of their native range in many regions of the world. Non-native wild populations exist throughout North America, South America, Europe, and in many areas of Asia and Australia. Most introductions were either from released pets or discarded baitfish. Because goldfish are hardy and able to tolerate wide ranges of temperature, food type and water quality, they are often successful invaders.

Non-native goldfish populations have caused significant environmental harm. They have been linked to decreased water quality and increased toxic algal blooms. They have spread harmful parasites in Australia and caused the decline of rare native amphibians in Europe. Voracious predators on the eggs and young of aquatic animals, goldfish have reduced populations of native species almost everywhere they have been introduced.

EcoHealthy Recommendation:

Before obtaining any non-traditional pet, check that it is legal to own one in your state of residence and check for permitting requirements. Only acquire a pet that is from a reputable breeder or dealer to ensure that you are not buying an illegally imported or wild-caught animal. Always keep your pet inside a safe and secure enclosure. Never release a pet into the wild.

Ease of Care

Does harvest, captive breeding, transport, or being kept as a pet harm individual animals?

Some Cause for Concern

Ease of care of many non-traditional pets depends on the individual owner’s years of experience and knowledge caring for a particular species. For the purposes of this website, we have geared information toward the benefit of the beginner.

Goldfish are relatively easy to breed and keep in captivity. However they do require maintenance of proper water quality, temperature, and pH level. It is a common misconception that goldfish can be kept in fishbowls. Not only should the fish grow to a size much too large for a bowl but they also produce more ammonia than most fish and will fowl the water in a small container very quickly. This drastically reduces the oxygen available in the water and will cause the goldfish stress which can lead to illness and even death. Water should be changed using the appropriate technique every two weeks or so. Goldfish may live up to 30 years in captivity, requiring a long-term commitment of care. Regarding welfare, most breeding facilities are in Asia, so the fish must be shipped to pet stores in North America. In some instances, they are subjected to harsh conditions during transport and mortality in goldfish shipments can be high (up to 80%).

Goldfish are omnivorous. Most store-bought foods do not contain adequate plant matter and this can lead to intestinal problems and common swim bladder infections. For this reason, peas can serve as a great additive to a goldfish diet.

EcoHealthy Recommendation:

Before acquiring a goldfish, be sure to research its specific care requirements and be prepared to care for this animal for up to 30 years. If possible, purchase a goldfish that has been domestically bred to reduce the likelihood they have suffered during transport.

Health Threat

Does this animal pose a health risk to native wildlife, humans, livestock and agriculture?

Some Cause for Concern

Goldfish are known to carry bacteria (Mycobacteria species) that can cause disease in fish and skin infections in humans. Even healthy-looking fish may be infected by these bacteria. People with compromised immune systems are susceptible to these skin infections, commonly known as “fish-handler’s disease.”

EcoHealthy Recommendation:

Due to the potential for disease transmission to humans and other household pets, always wash your hands after handling a fish or touching the aquarium water. When purchasing a pet fish ask the seller if the fish or group of fish has a history of any health problems and for a list of any medical treatments the animal or tank has received.

EcoHealth Alliance works at the intersection of ecosystem, animal and human health through local conservation programs and develops global health solutions to emerging diseases.
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