Can bettas live with koi?

Verdict

No. Bettas and koi should not share a tank. Koi are coldwater animals (59–77°F); bettas need 76–82°F. They overlap only at 76–77°F, the edge of both ranges.

Betta76–82°F · pH 6.5–7.5

Koi59–77°F · pH 7–8.5

What to watch

Deal breakerKoi are coldwater animals (59–77°F); bettas need 76–82°F. They overlap only at 76–77°F, the edge of both ranges.
Watch outAt 24 inches a koi can swallow a small betta. Fast, alert fish usually stay out of reach.

What works

pH 7–7.5 suits both.

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

	Betta	Koi
Temperature	76–82 °F	59–77 °F
pH	6.5–7.5	7–8.5
Adult size	2.5 in	24.0 in
Minimum tank	5 gal	Pond
Temperament	Semi-aggressive	Peaceful
Swims at	Top	All levels
Group	One per tank	Groups of 3+
Diet	Carnivore	Omnivore

Better tank mates for bettas

All betta tank mates

Better tank mates for koi