Can killifish live with black skirt tetras?

Verdict
Yes

Yes, killifish and black skirt tetras can live together. Both are fine at 70–77°F. Plan on at least 15 gal.

KillifishKillifish70–77°F · pH 5.5–7 Black skirt tetraBlack skirt tetra70–80°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°Black skirt tetra 70–80°
The green band is the temperature range both can live in.
456789Both: 6–7Killifish 5.5–7Black skirt tetra 6–7.5
The green band is the pH both tolerate.

Size to scale

Killifish · 2.5 inBlack skirt tetra · 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

KillifishBlack skirt tetra
Temperature70–77 °F70–80 °F
pH5.5–76–7.5
Adult size2.5 in2.5 in
Minimum tank10 gal15 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 black skirt tetras

All black skirt tetra tank mates

Questions

Can killifish live with black skirt tetras?

Yes, killifish and black skirt tetras can live together. Both are fine at 70–77°F. Plan on at least 15 gal.

What temperature suits both killifish and black skirt tetras?

70–77 °F. Killifish need 70–77 °F, black skirt tetras need 70–80 °F.

What size tank do killifish and black skirt tetras need together?

At least 15 gal, set by the black skirt tetra. Add space for each extra fish.