Can koi live with tinfoil barbs?

Verdict
Yes

Yes, koi and tinfoil barbs can live together. Both are fine at 72–77°F. Plan on at least Pond.

KoiKoi59–77°F · pH 7–8.5 Tinfoil barbTinfoil barb72–80°F · pH 6.5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 72–77°Koi 59–77°Tinfoil barb 72–80°
The green band is the temperature range both can live in.
456789Both: 7–7.5Koi 7–8.5Tinfoil barb 6.5–7.5
The green band is the pH both tolerate.

Size to scale

Koi · 24 inTinfoil barb · 12 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

KoiTinfoil barb
Temperature59–77 °F72–80 °F
pH7–8.56.5–7.5
Adult size24.0 in12.0 in
Minimum tankPond125 gal
TemperamentPeacefulPeaceful
Swims atAll levelsMiddle
GroupGroups of 3+Groups of 5+
DietOmnivoreOmnivore

Better tank mates for koi

All koi tank mates

Better tank mates for tinfoil barbs

All tinfoil barb tank mates

Questions

Can koi live with tinfoil barbs?

Yes, koi and tinfoil barbs can live together. Both are fine at 72–77°F. Plan on at least Pond.

What temperature suits both koi and tinfoil barbs?

72–77 °F. Koi need 59–77 °F, tinfoil barbs need 72–80 °F.

What size tank do koi and tinfoil barbs need together?

A pond. Koi outgrow indoor tanks.