Can killifish live with rosy barbs?

Verdict
Yes

Yes, killifish and rosy barbs can live together. Both are fine at 70–77°F. Plan on at least 30 gal.

KillifishKillifish70–77°F · pH 5.5–7 Rosy barbRosy barb64–77°F · pH 6–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 70–77°Killifish 70–77°Rosy barb 64–77°
The green band is the temperature range both can live in.
456789Both: 6–7Killifish 5.5–7Rosy barb 6–7.5
The green band is the pH both tolerate.

Size to scale

Killifish · 2.5 inRosy barb · 4 in0"1"2"3"4"5"6"
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

KillifishRosy barb
Temperature70–77 °F64–77 °F
pH5.5–76–7.5
Adult size2.5 in4.0 in
Minimum tank10 gal30 gal
TemperamentPeacefulSemi-aggressive
Swims atTopMiddle
GroupAlone or in pairsGroups of 6+
DietCarnivoreOmnivore

Better tank mates for killifish

All killifish tank mates

Better tank mates for rosy barbs

All rosy barb tank mates

Questions

Can killifish live with rosy barbs?

Yes, killifish and rosy barbs can live together. Both are fine at 70–77°F. Plan on at least 30 gal.

What temperature suits both killifish and rosy barbs?

70–77 °F. Killifish need 70–77 °F, rosy barbs need 64–77 °F.

What size tank do killifish and rosy barbs need together?

At least 30 gal, set by the rosy barb. Add space for each extra fish.