Fancy goldfish care
Carassius auratus · Bred from wild carp of East Asia
Fancy goldfish need far more room than a bowl: about 20 gallons for the first fish and 10 more for each one after, with strong filtration and weekly water changes, because they produce a lot of waste.
- Tank size
- 20 US gal or larger
- Temperature
- 64 to 74 °F (18 to 23 °C)
- Group size
- 2 or more
- Temperament
- Peaceful
- Adult size
- 8 in (including the tail)
- pH
- 7 to 8
- Hardness (GH)
- 6 to 18 dGH
- Lifespan
- 10 to 15 years
- Diet
- Omnivore
- Care level
- Easy
In a 20 gallon long
30¼ × 12½ × 12¾ in outsideHow to keep fancy goldfish
Fancy goldfish need far more room than a bowl: about 20 gallons for the first fish and 10 more for each one after, with strong filtration and weekly water changes, because they produce a lot of waste. That is the long-standing rule; many current guides start at 30 gallons for one fish and add 15 to 20 for each one after, and the extra water stays cleaner. They are social, so keep two or more, at room temperature (64 to 74 °F), with other fancy goldfish rather than tropical fish.
Diet: Omnivore: sinking goldfish pellets, blanched peas and greens, frozen foods. What to feed goldfish · how often to feed.
Where they swim: All levels.
Fancy 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.
Oranda
8 in · 30+ gal · 64–74 °F
Ryukin
8 in · 30+ gal · 64–74 °F
Pearlscale goldfish
8 in · 30+ gal · 65–74 °F
Ranchu goldfish
8 in · 30+ gal · 65–74 °F
Fantail goldfish
8 in · 30+ gal · 64–74 °F
Black moor
6 in · 30+ gal · 64–74 °F
Lionhead goldfish
6 in · 30+ gal · 64–74 °F
Bubble eye goldfish
4 in · 30+ gal · 65–74 °F
Keep apart
Neon tetra: Adult fancy goldfish eat fish under about 2 in; neon tetras grow to 1.6 in.
Cardinal tetra: Adult fancy goldfish eat fish under about 2 in; cardinal tetras grow to 1.2 in.
Black neon tetra: Adult fancy goldfish eat fish under about 2 in; black neon tetras grow to 1.5 in.
Green neon tetra: Adult fancy goldfish eat fish under about 2 in; green neon tetras grow to 1 in.
Ember tetra: Adult fancy goldfish eat fish under about 2 in; ember tetras grow to 1.2 in.
Glowlight tetra: Adult fancy goldfish eat fish under about 2 in; glowlight tetras grow to 1.5 in.
What a fancy goldfish tank needs
A tank of 20 US gallons or more (such as the 20 gallon long) with a cover, and the equipment below. Fancy goldfish are comfortable at room temperature, so a heater is optional in a normal home.
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Aqueon PRO QuietFlow Power Filter 10
Rated by the maker for up to 20 US gal, which covers a 20 gallon fancy goldfish tank without being built for a far bigger one.
Aqueon QuietFlow Internal Power Filter 15–30 gal
Rated by the maker for 15–30 US gal, which covers a 20 gallon fancy 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 fancy 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, so you know it stays within 64 to 74 °F.
More choices, each with the reason it is in or out: Filters for a 20 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 fancy goldfish problems
- Floating upside down or struggling to swim (swim bladder trouble) has several causes, including infection. Many keepers soak or sink the food and feed blanched peas; if it does not improve in clean water, see a vet who treats fish.
- Ammonia burns and red streaks in small tanks; test and change water.
- Single-tail goldfish (comets) outgrow aquariums and belong in ponds.
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.
- Fancy goldfish Benson Kua, CC BY-SA 2.0, via Wikimedia Commons
- Oranda Lawrencekhoo, CC BY-SA 4.0, via Wikimedia Commons
- Ryukin Lawrencekhoo, CC BY-SA 4.0, via Wikimedia Commons
- Pearlscale goldfish Lerdsuwa, CC BY-SA 3.0, via Wikimedia Commons
- Ranchu goldfish Lerdsuwa, CC BY-SA 4.0, via Wikimedia Commons
- Fantail goldfish Pogrebnoj-Alexandroff, CC BY 3.0, via Wikimedia Commons
- Black moor Riyad Youssef, CC BY 2.5, via Wikimedia Commons
- Lionhead goldfish Roderick Santos, CC BY 2.5, via Wikimedia Commons
- Bubble eye goldfish Angie Torres from Toronto, CC BY-SA 2.0, 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
- 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
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