Can goldfish live with cardinal tetras?

Verdict

No. Goldfish and cardinal tetras should not share a tank. Goldfish are coldwater animals (60–74°F); cardinal tetras need 76–84°F. No temperature suits both.

Goldfish60–74°F · pH 7–8

Cardinal tetra76–84°F · pH 4.6–7

What to watch

Deal breakerGoldfish are coldwater animals (60–74°F); cardinal tetras need 76–84°F. No temperature suits both.
Watch outWater chemistry is a squeeze. The only pH that suits both is around 7.
Watch outAt 10 inches a goldfish can swallow a small cardinal tetra. Fast, alert fish usually stay out of reach.

Water side by side

The ranges do not meet, so one of them would always be too warm or too cold.

The green band is the pH both tolerate.

Size to scale

Adult length in an aquarium. A fish can swallow anything that fits in its mouth, roughly a third to half its own length for predators.

Care at a glance

	Goldfish	Cardinal tetra
Temperature	60–74 °F	76–84 °F
pH	7–8	4.6–7
Adult size	10.0 in	2.0 in
Minimum tank	40 gal	20 gal
Temperament	Peaceful	Peaceful
Swims at	All levels	Middle
Group	Alone or in pairs	Groups of 6+
Diet	Omnivore	Omnivore

Better tank mates for goldfish

All goldfish tank mates

Better tank mates for cardinal tetras

All cardinal tetra tank mates

Questions

Can goldfish live with cardinal tetras?

No. Goldfish and cardinal tetras should not share a tank. Goldfish are coldwater animals (60–74°F); cardinal tetras need 76–84°F. No temperature suits both.

What temperature suits both goldfish and cardinal tetras?

None. Goldfish need 60–74 °F and cardinal tetras need 76–84 °F, so the ranges do not meet.

What size tank do goldfish and cardinal tetras need together?

At least 40 gal, set by the goldfish. Add space for each extra fish.