One species · 12 varieties

Goldfish varieties

Carassius auratus

Every goldfish on this page is the same species, bred over centuries into different bodies and tails. The varieties do not share one setup: single-tails are pond fish that outgrow almost any tank, while fancies stay smaller and suit life indoors. Pick the band that fits your space first, then pick the form.

Pick a variety

2 bands · care differs

Single-tail · pond or very large tank

50 gal (190 L) minimum · grows to 9.8–11.8 in (25–30 cm) · 39–75°F (4–24°C) · pH 6.5–8.0

Fancy · tank

20–30 gal (75–114 L) minimum · grows to 5.9–9.8 in (15–25 cm) · 59–75°F (15–24°C) · pH 6.5–8.0

What differs between the bands

Single-tailFancy

Minimum tank50 gal (190 L)20–30 gal (75–114 L)

Adult size9.8–11.8 in (25–30 cm)5.9–9.8 in (15–25 cm)

Temperature39–75°F (4–24°C)59–75°F (15–24°C)

Homepond or very large tankindoor tank

Swimmingfast and strongslow, easily outcompeted

The same for every variety: cold water, no heater, a big appetite and a heavy waste load. Plan on strong filtration whichever band you pick.

One species, many bodies

Goldfish were domesticated from a wild, silver-brown carp in China roughly a thousand years ago, and every variety since has come from selecting body, tail, eye and head mutations within the same species. A comet and a bubble eye are as closely related as two littermates; the differences are entirely bred, which is why the bands differ in what they can live in but not in what they are.

Keeping varieties together

Fancy varieties mix well with each other: they swim at the same slow pace and compete evenly for food. Keep single-tails with single-tails. They are faster, take the food first, and need colder water and far more space than a fancy setup provides. The delicate-eyed forms, bubble eye, celestial eye and black moor, do best with equally slow tank mates and nothing sharp in the tank.

Common questions

Can fancy and single-tail goldfish share a tank?

No. Single-tails are faster and take the food first, and the two bands want different space and temperatures. Varieties within a band mix well.

Do goldfish need a heater?

No. Every variety is a coldwater fish. Fancies are most comfortable at 59–75°F (15–24°C); single-tails handle 39–75°F (4–24°C) and can overwinter in a deep enough pond.

How big do goldfish really get?

Far bigger than the bowl myth. Single-tails reach 10–12 in (25–30 cm) and belong in ponds or very large tanks; fancies stay 6–10 in (15–25 cm) and want 20 gal (75 L) or more each.