Ryukin (fancy) (Carassius auratus) in a freshwater aquarium
Intermediate carePeacefulAll dwellerEast Asia

Ryukin (fancy)

Carassius auratus

The Ryukin (fancy) (Carassius auratus) is a peaceful fish that's a good step up once you have a little experience. Give it a tank of at least 140 litres (37 US gallons), water held at 61-73°F, and a pH of 6.5-8.

Care levelIntermediate
TemperamentPeaceful
Min tank size37 US gal
pH range6.5-8
Temperature61-73°F
Max size7.9 in (20.0 cm)
Captive lifespan10-25 years
SchoolingNo
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Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.

Natural distribution

East Asia

  • East & Southeast Asia

Regional colours match the stocking calculator's origin map.

Ryukin (fancy) Tank Setup

Goldfish need at least 140 litres (37 US gallons) with powerful filtration and cooler water around 61-73°F, pH 6.5-8. They produce far more waste than most tropical fish, so don't skimp on the filter. They reach about 20 cm as adults, so don't be misled by the small juveniles sold in stores.

What Do Ryukins Eat?

They're not fussy eaters - feed a varied diet, rotating good-quality dry, frozen, and gel foods rather than the same thing every day, and match the food size to their mouths.

Ryukin (fancy) Tank Mates

Deep-bodied; can be prone to buoyancy issues if overfed The Ryukin (fancy) is peaceful, which is the first thing to weigh up when you choose tank mates. At around 20 cm fully grown, it needs tank mates that can hold their own against its size and appetite. Before you buy, run your full stocking list through our stocking calculator. It weighs temperament, adult size, and water needs together, which a single species page can't do on its own.

Are Ryukins Good for Beginners?

Doable once you test water regularly and catch problems before fish look sick. If this is your first tank, pick something more forgiving and come back later.

Ryukin (fancy) - frequently asked questions

What size tank do Ryukins need?

Ryukins need a tank of at least 140 litres (37 US gallons). A bigger tank is always easier to keep stable, and gives them more room to settle in and behave naturally.

What water parameters do Ryukins need?

Keep them at 61-73°F with a pH of 6.5-8, steady rather than chased to an exact figure. In a cycled tank, ammonia and nitrite should both read 0 ppm, with nitrate kept low through regular water changes.

What do Ryukins eat?

Ryukins are omnivores and aren't fussy eaters. Feed a varied mix of good-quality dry, frozen, and gel foods, and match the food size to their mouths. Feed small amounts once or twice a day, and remove anything they don't eat.

Are Ryukins good for beginners?

Ryukins are best for keepers with a little experience. They are manageable once you test water regularly and catch problems early; a complete beginner may prefer something more forgiving first.

Common mistakes with Ryukins

  • Underestimating tank size - the minimum footprint is 140 litres (37 US gallons); impulse buying into a smaller tank leads to stress and shortened lifespan.

Building a community? Run the full list through the stocking calculator before you add anything else.

Fish to avoid mixing with Ryukins

These well-known species are commonly sold alongside this fish but are not recommended tank mates - verify before purchasing.

  • OscarTropical fish - too warm for goldfish tanks
  • AxolotlTropical fish - too warm for goldfish tanks
  • Akar BettaTropical fish - too warm for goldfish tanks