How big does Goldfish get?

Goldfish reaches an adult standard length of 15–25 cm (excluding the caudal fin). Size the tank for that, not for the juvenile you bring home — the difference is often several times over, and upgrading later costs more than buying once.

What water does Goldfish need?

10–24 °C, pH 6.5–8, 5–20 dGH, 4–12 dKH. At 14 °C wide it is one of the more forgiving ranges.

What is the smallest tank for Goldfish?

At least 120 L, and no shorter than 90 cm. That is the floor for long-term keeping, not for short-term survival: volume buys water stability and length buys swimming room, and neither substitutes for the other. It is not a schooling fish, so a single specimen or a pair is fine.

What is Goldfish like to keep?

Temperament: peaceful. Difficulty: beginner. It occupies the middle and is omnivore. With plants it is "Eats plants".

Can Goldfish be kept with its most common tank mate?

The checker returns "Can be kept together". Goldfish and White Cloud Mountain Minnow is a well-established pairing. Individual fish still differ; the record says "usually fine", not "guaranteed".

G-01 / 31Freshwater

Goldfish金鱼

Carassius auratus · Cyprinidae

The archetypal cold-water fish: a heavy eater and polluter that suffers alongside tropical tankmates.

Illustration to come

G-01 / 31 · Goldfish Carassius auratus

SpecificationsFish atlas

Name: 金鱼
Scientific name: Carassius auratus
Family: Cyprinidae
Origin: China (bred over centuries from the Prussian carp)
Adult size: 15–25 cm
Temperament: Peaceful
Diet: Omnivore
Water level: Middle
Level: Beginner
Min. tank: 120 L
Min. length: 90 cm
Plant safe: Eats plants

Water requirementsFreshwater

Temp.10–24 °C

pH6.5–8

Hardness5–20 dGH

Alkalinity4–12 dKH

Units: temperature in °C, hardness in German degrees (dGH / dKH), marine salinity as specific gravity at 25 °C, volume in litres. These are the values recorded for the species and do not follow the site unit switcher.

Keeping notes

1Happiest at 10-24 °C; sharing a tank long term with tropicals needing 26 °C+ harms both.
2Heavy eaters and polluters: size filtration at five times the tank volume and change 30 % weekly.
3Eats nearly every plant, so only hard-leaved species such as Anubias and Java fern survive with it.
4Start at 120 L for one adult; fancy varieties swim slowly, so avoid sharp decor.
5Omnivorous on goldfish pellets plus blanched vegetables, fed once daily and sparingly.

Check a tank mate

Jump straight to the verdict for Goldfish against this one — no need to pick it again.

Frequently asked questions

How big does Goldfish get?: Goldfish reaches an adult standard length of 15–25 cm (excluding the caudal fin). Size the tank for that, not for the juvenile you bring home — the difference is often several times over, and upgrading later costs more than buying once.
What water does Goldfish need?: 10–24 °C, pH 6.5–8, 5–20 dGH, 4–12 dKH. At 14 °C wide it is one of the more forgiving ranges.
What is the smallest tank for Goldfish?: At least 120 L, and no shorter than 90 cm. That is the floor for long-term keeping, not for short-term survival: volume buys water stability and length buys swimming room, and neither substitutes for the other. It is not a schooling fish, so a single specimen or a pair is fine.
What is Goldfish like to keep?: Temperament: peaceful. Difficulty: beginner. It occupies the middle and is omnivore. With plants it is "Eats plants".
Can Goldfish be kept with its most common tank mate?: The checker returns "Can be kept together". Goldfish and White Cloud Mountain Minnow is a well-established pairing. Individual fish still differ; the record says "usually fine", not "guaranteed".