Common goldfish care
Carassius auratus · Bred from wild carp of East Asia
Common goldfish are the plain, single-tailed goldfish sold as feeders and won at fairs, and they grow to about 9 inches or more and live 10 to 20 years.
- Tank size
- 75 US gal or larger
- Temperature
- 50 to 75 °F (10 to 24 °C)
- Group size
- 2 or more
- Temperament
- Peaceful
- Adult size
- 8.7 in (wild goldfish grow 4.7 to 8.7 in and can reach 16 in; pet goldfish vary with breed and tank)
- pH
- 7 to 8
- Hardness (GH)
- 6 to 18 dGH
- Lifespan
- 10 to 20 years
- Diet
- Omnivore
- Care level
- Easy
In a 75 gallon
48½ × 18½ × 21⅛ in outsideHow to keep common goldfish
Common goldfish are the plain, single-tailed goldfish sold as feeders and won at fairs, and they grow to about 9 inches or more and live 10 to 20 years. They belong in a pond, or in a 75 gallon or larger tank for a pair, with strong filtration: they produce a lot of waste.
Diet: Omnivore: sinking goldfish pellets, blanched peas and greens, frozen foods. Fish food types compared · how often to feed.
Where they swim: All levels.
Common goldfish tank mates
Share the temperature and water, and neither side eats, nips or bullies the other. Check the full group in the stocking checker.
Comet goldfish
10 in · 75+ gal · 50–75 °F
Shubunkin
12 in · 75+ gal · 50–75 °F
Dojo loach
10 in · 55+ gal · 55–77 °F
Rosy barb
6 in · 29+ gal · 64–77 °F
Denison barb
6 in · 55+ gal · 64–77 °F
Rubbernose pleco
5.7 in · 30+ gal · 68–77 °F
Blind cave tetra
4.7 in · 29+ gal · 68–77 °F
Butterfly goodeid
4 in · 30+ gal · 70–75 °F
Keep apart
Neon tetra: Adult common goldfish eat fish under about 2 in; neon tetras grow to 1.6 in.
Cardinal tetra: Adult common goldfish eat fish under about 2 in; cardinal tetras grow to 1.2 in.
Black neon tetra: Adult common goldfish eat fish under about 2 in; black neon tetras grow to 1.5 in.
Green neon tetra: Adult common goldfish eat fish under about 2 in; green neon tetras grow to 1 in.
Ember tetra: Adult common goldfish eat fish under about 2 in; ember tetras grow to 1.2 in.
Glowlight tetra: Adult common goldfish eat fish under about 2 in; glowlight tetras grow to 1.5 in.
What a common goldfish tank needs
A tank of 75 US gallons or more (such as the 75 gallon) with a cover, and the equipment below. Common goldfish are comfortable at room temperature, so a heater is optional in a normal home.
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Aqueon QuietFlow Canister Filter 300
Rated by the maker for 55–75 US gal, which covers a 75 gallon common goldfish tank without being built for a far bigger one.
Marineland Penguin PRO 375
Rated by the maker for up to 75 US gal, which covers a 75 gallon common goldfish tank without being built for a far bigger one.
API Freshwater Master Test Kit
Tests ammonia, nitrite, nitrate and pH, the readings that matter most before and after adding common goldfish.
Seachem Prime 100 mL
Removes chlorine and chloramine from tap water at every water change.
Fluval Edge Thermometer
Shows the water temperature at a glance, but its display reads 64 to 86 °F, so it can’t show the bottom of the 50 to 75 °F common goldfish range. Check it with a second thermometer that reads below 64 °F.
More choices, each with the reason it is in or out: Filters for a 75 gallon tank. We don’t list fish food: any good brand of the foods under Diet will do. Plan the whole tank's equipment →
Common goldfish problems
- In a bowl or small tank their waste builds up fast; they need far more room than most people expect.
- Fancy goldfish are slower and lose food to them; keep single-tailed goldfish with their own kind.
- Never release them: goldfish let go in the wild become invasive and grow large.
Test the water first whenever fish look unwell: see what your readings mean, then match the symptom. For disease, a vet who treats fish can diagnose it and advise treatment.
More to compare
Sources
Name, origin and adult size checked against Wikipedia: Carassius auratus. Temperature, pH, hardness, group size, lifespan and minimum tank size are common hobby guidance, not figures from that article. Ranges are the range the species tolerates; aim for the middle. Minimum tank sizes are for an adult group. Drawings are our own; photo credits follow.
Photo credits
Real photographs from Wikimedia Commons, resized and cropped to fit; each is used under the license named.
- Common goldfish ぱたごん, CC BY-SA 3.0, via Wikimedia Commons
- Comet goldfish Michelle Jo (Humanfeather), CC BY 3.0, via Wikimedia Commons
- Shubunkin Rodsan18 at English Wikipedia, CC BY 2.5, via Wikimedia Commons
- Dojo loach PrinceNimblesoft, CC0, via Wikimedia Commons
- Rosy barb Kkonstan, CC BY 3.0, via Wikimedia Commons
- Denison barb Anandarajkumar, CC BY-SA 3.0, via Wikimedia Commons
- Rubbernose pleco Frank Alvarez, CC BY 3.0, via Wikimedia Commons
- Blind cave tetra James St. John, CC BY 2.0, via Wikimedia Commons
- Butterfly goodeid Przemysław Malkowski, CC BY-SA 3.0, via Wikimedia Commons
- Neon tetra Holger Krisp, CC BY 3.0, via Wikimedia Commons
- Cardinal tetra CHUCAO, CC BY-SA 3.0, via Wikimedia Commons
- Black neon tetra Debivort, CC BY-SA 3.0, via Wikimedia Commons
- Green neon tetra Sascha Biedermann, CC BY-SA 2.5, via Wikimedia Commons
- Ember tetra Klaus Rudloff, CC BY-SA 4.0, via Wikimedia Commons
- Glowlight tetra gonzalovalenzuela; cropped by Kyknos, CC BY 2.0, via Wikimedia Commons
- Fancy goldfish Benson Kua, CC BY-SA 2.0, via Wikimedia Commons
- Oranda Lawrencekhoo, CC BY-SA 4.0, via Wikimedia Commons
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