Can corydoras live with pencilfish?

Verdict
Yes

Yes. Corydoras and pencilfish get along in the same tank. Both are fine at 75–79°F. Plan on at least 20 gal.

CorydorasCorydoras72–79°F · pH 6–7.8 PencilfishPencilfish75–82°F · pH 5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–79°Corydoras 72–79°Pencilfish 75–82°
The green band is the temperature range both can live in.
456789Both: 6–7.5Corydoras 6–7.8Pencilfish 5–7.5
The green band is the pH both tolerate.

Size to scale

Corydoras · 2.5 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

CorydorasPencilfish
Temperature72–79 °F75–82 °F
pH6–7.85–7.5
Adult size2.5 in2.0 in
Minimum tank20 gal15 gal
TemperamentPeacefulPeaceful
Swims atBottomMiddle
GroupGroups of 6+Groups of 6+
DietOmnivoreOmnivore

Better tank mates for corydoras

All corydoras tank mates

Better tank mates for pencilfish

All pencilfish tank mates

Questions

Can corydoras live with pencilfish?

Yes. Corydoras and pencilfish get along in the same tank. Both are fine at 75–79°F. Plan on at least 20 gal.

What temperature suits both corydoras and pencilfish?

75–79 °F. Corydoras need 72–79 °F, pencilfish need 75–82 °F.

What size tank do corydoras and pencilfish need together?

At least 20 gal, set by the corydoras. Add space for each extra fish.