FisheasyFreshwater

Goldfish

Carassius auratus

Animalia›Chordata›Actinopterygii›Cypriniformes›Cyprinidae

Carassius auratus is the goldfish, domesticated in China from a wild carp more than a thousand years ago. Single-tailed goldfish such as the Common, Comet and Shubunkin grow to about 12 inches and suit ponds or very large tanks. The fancy goldfish, with egg-shaped bodies and double tails, stay smaller, swim more slowly and are best kept apart from them. All of them are coldwater fish that produce a lot of waste, so they need strong filtration and regular water changes.

Where it's from

Native to the Amu Darya, Amur, Ansan, Anseongcheon and 276 other river basins

Uzbekistan, China, South Korea, Taiwan, North Korea, Russia, Laos, Malaysia and 1 more

Recorded as introduced in Greece (Acheloos basin), Japan (Adako un basin), Afghanistan, United States (Alabama basin) and 399 more places

At a glance

Size: 12 in; 30 cm
Min tank: 50 gal; 189 L
Group: 2+
Temp: 54–75°F; 12–24°C
pH: 6.5–7.5
GH: 89–339 ppm; 5–19 dGH
Temperament: Peaceful
Swims: All levels
Lifespan: 10–15+ yrs

Ammonia 0 ppm and nitrate under 20 ppm.

Tanks keeping this

Kept by 7 members

By morph. 3 tanks shared publicly; 4 more kept privately.

Common Goldfish3 tanks · 2 private

50 gallon

@nicholastramutola

Common Goldfish page

Black Moor Goldfish2 tanks · 1 private

Black Moor Aquarium

@tragic

Black Moor Goldfish page

Oranda Goldfish2 tanks · all private

Kept only in private tanks so far.

Oranda Goldfish page

Comet Goldfish1 tank

Sunshine Shore

@autumnphilippi

Comet Goldfish page

Fantail Goldfish1 tank · all private

Kept only in private tanks so far.

Fantail Goldfish page

Care

Diet

Goldfish are omnivores and should be fed high-quality goldfish pellets or flakes as their staple diet, supplemented 2-3 times weekly with vegetables like blanched peas, spinach, and zucchini. Occasional treats of bloodworms or brine shrimp provide protein variety. Feed once daily, only what they can consume in 2-3 minutes, as overfeeding causes water quality issues and health problems.

Behavior

Goldfish are active, fast swimmers that spend most of their time in the middle to lower water column searching for food. They are peaceful and social, thriving best in pairs or small groups, though they may uproot plants and stir substrate while foraging. They are curious and can recognize their owners, often begging at feeding time.

Breeding

Breeding goldfish in captivity is possible but requires large tanks (75+ gallons), cooler water temperatures (16-18°C), and seasonal conditioning with live foods. Females scatter thousands of adhesive eggs on plants or spawning mops, and parents will eat eggs and fry if not separated. Fry are difficult to raise and require infusoria or liquid fry food initially.

Tank mates

See all 3

Gold Mystery Snail

Peaceful snail that helps with algae control; goldfish may occasionally harass but snails can retreat into shells

good

Ramshorn Snail

Hardy snail that tolerates goldfish behavior; helps maintain tank cleanliness without competing for food

good

Nerite Snail

Durable snail with hard shell; excellent algae eater that coexists peacefully with goldfish

good

Fits a 55-gallon tank Beginner-friendly Peaceful

Black Moor Goldfish· 2 tanks Bristol Shubunkin Bubble Eye Goldfish Celestial Eye Goldfish Comet Goldfish· 1 tank Common Goldfish· 3 tanks Fancy Goldfish Fantail Goldfish· 1 tank Lionhead Goldfish London Shubunkin Oranda Goldfish· 2 tanks Pearlscale Goldfish Pompom Goldfish Ranchu Goldfish Ryukin Goldfish Shubunkin Goldfish Telescope Goldfish

Legality

No state or federal restrictions on record.

Not legal advice, and possibly incomplete or out of date. Rules vary by state and change over time; check with your state wildlife or agriculture agency before buying, keeping or shipping it.

The care information here is written with AI help, so it can contain mistakes. Spot one? Tell us and we'll fix it. Native range: DAISIE (CC BY 4.0); Global Register of Introduced and Invasive Species (CC BY 4.0); Waarnemingen.be / observations.be (CC BY 4.0); GRIIS Checklist of Introduced and Invasive Species (CC BY 4.0); Protected Areas - Global Register of Introduced and Invasive Species (CC BY 4.0); Global Register of Invasive and Introduced Species (CC BY 4.0); A list of the terrestrial and marine biota from the Azores (CC BY 4.0); Global Register of Introduced and Invasive Species -Samoa (CC BY 4.0); Tedesco et al. 2017 (CC0).