Can koi live with jack dempseys?

Verdict

Yes, with care

Yes, with care. Koi and jack dempseys can share a tank, but watch one thing. Jack dempseys are aggressive, though koi are big enough to shrug most of it off.

Koi59–77°F · pH 7–8.5

Jack Dempsey72–86°F · pH 6.5–7.5

What to watch

Watch outJack dempseys are aggressive, though koi are big enough to shrug most of it off.

What works

Both are fine at 72–77°F.
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

	Koi	Jack Dempsey
Temperature	59–77 °F	72–86 °F
pH	7–8.5	6.5–7.5
Adult size	24.0 in	10.0 in
Minimum tank	Pond	55 gal
Temperament	Peaceful	Aggressive
Swims at	All levels	Middle
Group	Groups of 3+	Alone or in pairs
Diet	Omnivore	Carnivore

Better tank mates for koi

All koi tank mates

Better tank mates for jack dempseys

CrayfishYes