Can plecos live with killifish?

Verdict

Yes, with care

Yes, with care. Plecos and killifish can share a tank, but watch one thing. Plecos grow to 15 inches and need 125 gallons, far more than a tank set up for killifish.

Common pleco72–86°F · pH 6.5–7.5

Killifish70–77°F · pH 5.5–7

What to watch

Watch outPlecos grow to 15 inches and need 125 gallons, far more than a tank set up for killifish.

What works

Both are fine at 72–77°F.
pH 6.5–7 suits both.
They use different parts of the tank: plecos the bottom, killifish the top.

Water side by side

The green band is the temperature range both can live in.

The green band is the pH both tolerate.

Size to scale

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

	Common pleco	Killifish
Temperature	72–86 °F	70–77 °F
pH	6.5–7.5	5.5–7
Adult size	15.0 in	2.5 in
Minimum tank	125 gal	10 gal
Temperament	Peaceful	Peaceful
Swims at	Bottom	Top
Group	Alone or in pairs	Alone or in pairs
Diet	Herbivore	Carnivore

Better tank mates for plecos

All common pleco tank mates

Better tank mates for killifish