Species · Carassius auratus (single-tail forms)

Common / comet goldfish: tank size, water and tank mates

FLAG: coldwater, grows to ~30 cm, very heavy waste; a pond fish long-term; do not mix with tropicals.

Adult size30 cm (11.8 in)
Minimum tank50 US gal
Temperature10–21 °C (50–70 °F)
pH6–8
Temperamentpeaceful
Keep in groups ofAlone or pairs
Swimsall
Shrimp & snailsCaution

Predator: may eat fish up to about 2 cm.

Check a tank with Common / comet goldfish

Good tank mates for Common / comet goldfish

These species share its temperature range and temperament, with no fin-nipping or predation risk under our rules. Still check your tank size and bioload in the checker.

Bloodfin tetra · Buenos Aires tetra · Celestial pearl danio · Checkerboard barb · Clown killifish · Colombian tetra · Fancy goldfish · Gold barb · Guppy · Indian glassfish · Medaka · Odessa barb · Pearl danio · Reticulated hillstream loach · Rosy barb · Tiger barb · Turquoise rainbowfish · Variatus platy · White cloud mountain minnow · Zebra danio

Avoid with Common / comet goldfish

African butterflyfish (temperature) · African dwarf frog (temperature) · Agassiz's dwarf cichlid (temperature) · Angelfish (temperature) · Assassin snail (temperature) · Bala shark (temperature) · Banded archerfish (temperature) · Banjo catfish (temperature) · Betta (male) (temperature) · Black ghost knifefish (temperature) · Black neon tetra (temperature) · Black phantom tetra (temperature) · Black ruby barb (temperature) · Black skirt tetra (temperature) · Bleeding heart tetra (temperature) · Blue acara (temperature) · Boeseman's rainbowfish (temperature) · Bolivian ram (temperature)

Sources

Checked 2026-11-09 · confidence: medium. These are cautious community guidelines, not guarantees. Not veterinary advice. Report an error.