Can plecos live with pencilfish?

Verdict

Yes, with care

Yes, with care. Plecos and pencilfish 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 pencilfish.

Common pleco72–86°F · pH 6.5–7.5

Pencilfish75–82°F · pH 5–7.5

What to watch

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

What works

Both are fine at 75–82°F.
pH 6.5–7.5 suits both.
They use different parts of the tank: plecos the bottom, pencilfish the mid.

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	Pencilfish
Temperature	72–86 °F	75–82 °F
pH	6.5–7.5	5–7.5
Adult size	15.0 in	2.0 in
Minimum tank	125 gal	15 gal
Temperament	Peaceful	Peaceful
Swims at	Bottom	Middle
Group	Alone or in pairs	Groups of 6+
Diet	Herbivore	Omnivore

Better tank mates for plecos

All common pleco tank mates

Better tank mates for pencilfish