Can bristlenose plecos live with pencilfish?

Verdict
Yes

Yes, bristlenose plecos and pencilfish can live together. Both are fine at 75–81°F. Plan on at least 30 gal.

Bristlenose plecoBristlenose pleco73–81°F · pH 6.5–7.5 PencilfishPencilfish75–82°F · pH 5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–81°Bristlenose pleco 73–81°Pencilfish 75–82°
The green band is the temperature range both can live in.
456789Both: 6.5–7.5Bristlenose pleco 6.5–7.5Pencilfish 5–7.5
The green band is the pH both tolerate.

Size to scale

Bristlenose pleco · 5 inPencilfish · 2 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

Bristlenose plecoPencilfish
Temperature73–81 °F75–82 °F
pH6.5–7.55–7.5
Adult size5.0 in2.0 in
Minimum tank30 gal15 gal
TemperamentPeacefulPeaceful
Swims atBottomMiddle
GroupAlone or in pairsGroups of 6+
DietHerbivoreOmnivore

Better tank mates for bristlenose plecos

All bristlenose pleco tank mates

Better tank mates for pencilfish

All pencilfish tank mates

Questions

Can bristlenose plecos live with pencilfish?

Yes, bristlenose plecos and pencilfish can live together. Both are fine at 75–81°F. Plan on at least 30 gal.

What temperature suits both bristlenose plecos and pencilfish?

75–81 °F. Bristlenose plecos need 73–81 °F, pencilfish need 75–82 °F.

What size tank do bristlenose plecos and pencilfish need together?

At least 30 gal, set by the bristlenose pleco. Add space for each extra fish.