Species profile
Fancy Goldfish
Carassius auratus
Peaceful
Moderate care
240 L minimum aquarium
20–30 cm adult size
Mid bottom
Minimum group: 2
About this species
General notes for hobby use.
Profile is for round-bodied fancy goldfish forms, not Common or Comet single-tail goldfish. Large adults, heavy waste production and social behaviour make small bowls/tanks unsuitable.
Water parameters
Suggested general range for long-term care.
Temperature
18–24 °C
pH
7–8
GH
5–20 dGH
KH
Not yet documented
Flow preference
Low–moderate
Data confidence
Verified
Behaviour
General behaviour traits used by TanksConnected compatibility checks.
Minimum group size
Minimum group: 2
Tank zone
Mid bottom
Territory level
None
Predation risk
Inverts
Bioload factor
3.5
Generally social and non-territorial. Keep with similarly mobile fancy forms; very fast single-tail goldfish can outcompete some heavy-bodied varieties.
Compatibility flags
Quick cautions for common tank-planning issues.
Fin nipper
No
Plant safe
Caution
Shrimp safe
No / caution
Snail safe
No / caution
Cave breeder
No
Digs substrate
Yes
Jump risk
Yes
Natural history & care
Research-backed context for long-term aquarium care.
Lifespan
15–20 years
Diet type
Omnivore
Minimum aquarium volume
240 L
Minimum footprint
120 × 45 cm
Accepted scientific name
Carassius auratus
Alternative names
Fancy Goldfish, Round-bodied Goldfish, Carassius auratus aquarium fancy forms
Native range
Domestic ornamental forms derived from Carassius auratus; the wild species is native to East Asia.
Natural habitat
Domestic aquarium fish. Provide a large, well-filtered footprint with open swimming room and no sharp décor that can damage long fins or protruding eyes.
Diet & feeding
Use a varied omnivorous diet with substantial plant/fibre content; avoid chronic overfeeding and dry-food-only regimens.
Breeding & sexing
Research-backed guidance for identifying sexes and reproductive behaviour.
Sexing
Mature males may develop breeding tubercles on gill covers and pectoral rays; females are often fuller when gravid.
Breeding
Seasonal egg scatterer; adhesive eggs are deposited over plants or spawning media and adults may eat eggs.