Can killifish live with yellow labs?

Verdict
No

No. Killifish and yellow labs should not share a tank. Different water: killifish want pH 5.5–7, yellow labs want pH 7.8–8.6.

KillifishKillifish70–77°F · pH 5.5–7 Electric yellow cichlidElectric yellow cichlid75–82°F · pH 7.8–8.6

What to watch

What works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–77°Killifish 70–77°Electric yellow cichlid 75–82°
The green band is the temperature range both can live in.
456789Killifish 5.5–7Electric yellow cichlid 7.8–8.6
No pH suits both. One would live in the wrong water all the time.

Size to scale

Killifish · 2.5 inElectric yellow cichlid · 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

KillifishElectric yellow cichlid
Temperature70–77 °F75–82 °F
pH5.5–77.8–8.6
Adult size2.5 in4.0 in
Minimum tank10 gal40 gal
TemperamentPeacefulSemi-aggressive
Swims atTopAll levels
GroupAlone or in pairsGroups of 4+
DietCarnivoreOmnivore

Better tank mates for killifish

All killifish tank mates

Better tank mates for yellow labs

All electric yellow cichlid tank mates

Questions

Can killifish live with yellow labs?

No. Killifish and yellow labs should not share a tank. Different water: killifish want pH 5.5–7, yellow labs want pH 7.8–8.6.

What temperature suits both killifish and yellow labs?

75–77 °F. Killifish need 70–77 °F, yellow labs need 75–82 °F.

What size tank do killifish and yellow labs need together?

At least 40 gal, set by the electric yellow cichlid. Add space for each extra fish.