Can killifish live with paradise fish?

Verdict
Yes

Yes. Killifish and paradise fish make a good pair. Both are fine at 70–77°F. Plan on at least 20 gal.

KillifishKillifish70–77°F · pH 5.5–7 Paradise fishParadise fish61–79°F · pH 6–8

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 70–77°Killifish 70–77°Paradise fish 61–79°
The green band is the temperature range both can live in.
456789Both: 6–7Killifish 5.5–7Paradise fish 6–8
The green band is the pH both tolerate.

Size to scale

Killifish · 2.5 inParadise fish · 3.5 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

KillifishParadise fish
Temperature70–77 °F61–79 °F
pH5.5–76–8
Adult size2.5 in3.5 in
Minimum tank10 gal20 gal
TemperamentPeacefulSemi-aggressive
Swims atTopTop
GroupAlone or in pairsOne per tank
DietCarnivoreOmnivore

Better tank mates for killifish

All killifish tank mates

Better tank mates for paradise fish

All paradise fish tank mates

Questions

Can killifish live with paradise fish?

Yes. Killifish and paradise fish make a good pair. Both are fine at 70–77°F. Plan on at least 20 gal.

What temperature suits both killifish and paradise fish?

70–77 °F. Killifish need 70–77 °F, paradise fish need 61–79 °F.

What size tank do killifish and paradise fish need together?

At least 20 gal, set by the paradise fish. Add space for each extra fish.