TankmateChecker

Can koi live with flowerhorns?

Verdict

No

No. Koi and flowerhorns should not share a tank. Koi are coldwater animals (59–77°F); flowerhorns need 80–89°F. No temperature suits both.

Koi

Koi59–77°F · pH 7–8.5

Flowerhorn

Flowerhorn80–89°F · pH 7–8

What to watch

Deal breakerKoi are coldwater animals (59–77°F); flowerhorns need 80–89°F. No temperature suits both.
Watch outFlowerhorns are aggressive, though koi are big enough to shrug most of it off.

What works

pH 7–8 suits both.

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

	Koi	Flowerhorn
Temperature	59–77 °F	80–89 °F
pH	7–8.5	7–8
Adult size	24.0 in	12.0 in
Minimum tank	Pond	75 gal
Temperament	Peaceful	Aggressive
Swims at	All levels	Middle
Group	Groups of 3+	One per tank
Diet	Omnivore	Carnivore

Better tank mates for koi

All koi tank mates

Questions

Can koi live with flowerhorns?

No. Koi and flowerhorns should not share a tank. Koi are coldwater animals (59–77°F); flowerhorns need 80–89°F. No temperature suits both.

What temperature suits both koi and flowerhorns?

None. Koi need 59–77 °F and flowerhorns need 80–89 °F, so the ranges do not meet.

What size tank do koi and flowerhorns need together?

A pond. Koi outgrow indoor tanks.