Species profile
Goldfish (Common / Comet)
Carassius auratus
Peaceful
Moderate care
750 L minimum aquarium
20–30 cm adult size
Mid bottom
Minimum group: 5
About this species
General notes for hobby use.
Common and Comet Goldfish are large social single-tail fish suited to ponds or genuinely large, long aquaria—not bowls or small starter tanks.
Water parameters
Suggested general range for long-term care.
Temperature
10–20 °C
pH
7.5–8.5
GH
Up to 25 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: 5
Tank zone
Mid bottom
Territory level
None
Predation risk
Small fish
Bioload factor
3.5
Social, active foragers that constantly browse substrate and plants. High waste output and adult swimming space are the dominant husbandry constraints.
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
Low
Natural history & care
Research-backed context for long-term aquarium care.
Lifespan
Not yet documented
Diet type
Omnivore
Minimum aquarium volume
750 L
Minimum footprint
180 × 60 cm
Accepted scientific name
Carassius auratus
Alternative names
Common Goldfish, Comet Goldfish, Single-tail Goldfish
Native range
Domesticated form of an East Asian Carassius lineage; aquarium and pond strains do not have a meaningful wild locality.
Natural habitat
Care reflects cool, oxygenated pond/large-aquarium conditions; ancestral Carassius use slow or still waters with vegetation and soft substrate.
Diet & feeding
Broad omnivore taking plant matter, detritus and invertebrates. Feed a varied goldfish diet with substantial vegetable content.
Breeding & sexing
Research-backed guidance for identifying sexes and reproductive behaviour.
Sexing
Breeding males develop tubercles on gill covers/pectoral rays; mature females become visibly fuller with eggs.
Breeding
Seasonal egg scatterer depositing adhesive eggs among plants or spawning media; adults provide no parental care and may eat eggs.