Can koi live with black neon tetras?

Verdict
Yes, with care

Yes, with care. Koi and black neon tetras can share a tank, but watch one thing. At 24 inches a koi can swallow a small black neon tetra. Fast, alert fish usually stay out of reach.

What to watch

What works

Water side by side

55°60°65°70°75°80°85°90°Both: 73–77°Koi 59–77°Black neon tetra 73–81°
The green band is the temperature range both can live in.
456789Both: 7–7.5Koi 7–8.5Black neon tetra 5.5–7.5
The green band is the pH both tolerate.

Size to scale

Koi · 24 inBlack neon tetra · 1.5 in0"6"12"18"24"
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

KoiBlack neon tetra
Temperature59–77 °F73–81 °F
pH7–8.55.5–7.5
Adult size24.0 in1.5 in
Minimum tankPond15 gal
TemperamentPeacefulPeaceful
Swims atAll levelsMiddle
GroupGroups of 3+Groups of 6+
DietOmnivoreOmnivore

Better tank mates for koi

All koi tank mates

Better tank mates for black neon tetras

All black neon tetra tank mates

Questions

Can koi live with black neon tetras?

Yes, with care. Koi and black neon tetras can share a tank, but watch one thing. At 24 inches a koi can swallow a small black neon tetra. Fast, alert fish usually stay out of reach.

What temperature suits both koi and black neon tetras?

73–77 °F. Koi need 59–77 °F, black neon tetras need 73–81 °F.

What size tank do koi and black neon tetras need together?

A pond. Koi outgrow indoor tanks.