TankmateChecker

Can goldfish live with killifish?

Verdict

Yes, with care

Yes, with care. Goldfish and killifish can share a tank, but watch one thing. Water chemistry is a squeeze. The only pH that suits both is around 7.

Goldfish

Goldfish60–74°F · pH 7–8

Killifish

Killifish70–77°F · pH 5.5–7

What to watch

Watch outWater chemistry is a squeeze. The only pH that suits both is around 7.
Watch outA grown goldfish may treat small killifish as food, especially at night.

What works

Both are fine at 70–74°F.

Water side by side

The green band is the temperature range both can live in.

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	Killifish
Temperature	60–74 °F	70–77 °F
pH	7–8	5.5–7
Adult size	10.0 in	2.5 in
Minimum tank	40 gal	10 gal
Temperament	Peaceful	Peaceful
Swims at	All levels	Top
Group	Alone or in pairs	Alone or in pairs
Diet	Omnivore	Carnivore

Better tank mates for goldfish

All goldfish tank mates

Better tank mates for killifish

All killifish tank mates

Questions

Can goldfish live with killifish?

Yes, with care. Goldfish and killifish can share a tank, but watch one thing. Water chemistry is a squeeze. The only pH that suits both is around 7.

What temperature suits both goldfish and killifish?

70–74 °F. Goldfish need 60–74 °F, killifish need 70–77 °F.

What size tank do goldfish and killifish need together?

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