Can rummy nose tetras live with killifish?

Verdict
Yes

Yes. Rummy nose tetras and killifish get along in the same tank. Both are fine at 75–77°F. Plan on at least 20 gal.

Rummy nose tetraRummy nose tetra75–84°F · pH 5.5–7 KillifishKillifish70–77°F · pH 5.5–7

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–77°Rummy nose tetra 75–84°Killifish 70–77°
The green band is the temperature range both can live in.
456789Both: 5.5–7Rummy nose tetra 5.5–7Killifish 5.5–7
The green band is the pH both tolerate.

Size to scale

Rummy nose tetra · 2 inKillifish · 2.5 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

Rummy nose tetraKillifish
Temperature75–84 °F70–77 °F
pH5.5–75.5–7
Adult size2.0 in2.5 in
Minimum tank20 gal10 gal
TemperamentPeacefulPeaceful
Swims atMiddleTop
GroupGroups of 6+Alone or in pairs
DietOmnivoreCarnivore

Better tank mates for rummy nose tetras

All rummy nose tetra tank mates

Better tank mates for killifish

All killifish tank mates

Questions

Can rummy nose tetras live with killifish?

Yes. Rummy nose tetras and killifish get along in the same tank. Both are fine at 75–77°F. Plan on at least 20 gal.

What temperature suits both rummy nose tetras and killifish?

75–77 °F. Rummy nose tetras need 75–84 °F, killifish need 70–77 °F.

What size tank do rummy nose tetras and killifish need together?

At least 20 gal, set by the rummy nose tetra. Add space for each extra fish.