TankmateChecker

Can plecos live with mollies?

Verdict

Yes, with care

Yes, with care. Plecos and mollies can share a tank, but watch one thing. Water chemistry is a squeeze. The only pH that suits both is around 7.5.

Common pleco

Common pleco72–86°F · pH 6.5–7.5

Molly

Molly72–82°F · pH 7.5–8.5

What to watch

Watch outWater chemistry is a squeeze. The only pH that suits both is around 7.5.
Watch outPlecos grow to 15 inches and need 125 gallons, far more than a tank set up for mollies.

What works

Both are fine at 72–82°F.
They use different parts of the tank: plecos the bottom, mollies 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	Molly
Temperature	72–86 °F	72–82 °F
pH	6.5–7.5	7.5–8.5
Adult size	15.0 in	4.0 in
Minimum tank	125 gal	20 gal
Temperament	Peaceful	Peaceful
Swims at	Bottom	Top
Group	Alone or in pairs	Groups of 3+
Diet	Herbivore	Omnivore

Better tank mates for plecos

All common pleco tank mates

Better tank mates for mollies

All molly tank mates

Questions

Can plecos live with mollies?

Yes, with care. Plecos and mollies can share a tank, but watch one thing. Water chemistry is a squeeze. The only pH that suits both is around 7.5.

What temperature suits both plecos and mollies?

72–82 °F. Plecos need 72–86 °F, mollies need 72–82 °F.

What size tank do plecos and mollies need together?

At least 125 gal, set by the common pleco. Add space for each extra fish.