Can koi live with firemouth cichlids?

Verdict

No. Koi and firemouth cichlids should not share a tank. Koi are coldwater animals (59–77°F); firemouth cichlids need 75–86°F. They overlap only at 75–77°F, the edge of both ranges.

Koi59–77°F · pH 7–8.5

Firemouth cichlid75–86°F · pH 6.5–8

What to watch

Deal breakerKoi are coldwater animals (59–77°F); firemouth cichlids need 75–86°F. They overlap only at 75–77°F, the edge of both ranges.
Watch outA grown koi may treat small firemouth cichlids as food, especially at night.

What works

pH 7–8 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	Firemouth cichlid
Temperature	59–77 °F	75–86 °F
pH	7–8.5	6.5–8
Adult size	24.0 in	6.0 in
Minimum tank	Pond	30 gal
Temperament	Peaceful	Semi-aggressive
Swims at	All levels	Bottom
Group	Groups of 3+	Alone or in pairs
Diet	Omnivore	Omnivore

Better tank mates for koi

All koi tank mates

Better tank mates for firemouth cichlids

All firemouth cichlid tank mates

Questions

Can koi live with firemouth cichlids?

No. Koi and firemouth cichlids should not share a tank. Koi are coldwater animals (59–77°F); firemouth cichlids need 75–86°F. They overlap only at 75–77°F, the edge of both ranges.

What temperature suits both koi and firemouth cichlids?

75–77 °F. Koi need 59–77 °F, firemouth cichlids need 75–86 °F.

What size tank do koi and firemouth cichlids need together?

A pond. Koi outgrow indoor tanks.