Can neon tetras live with pencilfish?

Verdict
Yes

Yes. Neon tetras and pencilfish get along in the same tank. Both are fine at 75–79°F. Plan on at least 15 gal.

Neon tetraNeon tetra72–79°F · pH 6–7 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°Neon tetra 72–79°Pencilfish 75–82°
The green band is the temperature range both can live in.
456789Both: 6–7Neon tetra 6–7Pencilfish 5–7.5
The green band is the pH both tolerate.

Size to scale

Neon tetra · 1.5 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

Neon tetraPencilfish
Temperature72–79 °F75–82 °F
pH6–75–7.5
Adult size1.5 in2.0 in
Minimum tank10 gal15 gal
TemperamentPeacefulPeaceful
Swims atMiddleMiddle
GroupGroups of 6+Groups of 6+
DietOmnivoreOmnivore

Better tank mates for neon tetras

All neon tetra tank mates

Better tank mates for pencilfish

All pencilfish tank mates

Questions

Can neon tetras live with pencilfish?

Yes. Neon tetras and pencilfish get along in the same tank. Both are fine at 75–79°F. Plan on at least 15 gal.

What temperature suits both neon tetras and pencilfish?

75–79 °F. Neon tetras need 72–79 °F, pencilfish need 75–82 °F.

What size tank do neon tetras and pencilfish need together?

At least 15 gal, set by the pencilfish. Add space for each extra fish.