Can tiger barbs live with pencilfish?

Verdict
Yes

Yes. Tiger barbs and pencilfish get along in the same tank. Both are fine at 75–81°F. Plan on at least 30 gal.

Tiger barbTiger barb72–81°F · pH 6–7.5 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°Tiger barb 72–81°Pencilfish 75–82°
The green band is the temperature range both can live in.
456789Both: 6–7.5Tiger barb 6–7.5Pencilfish 5–7.5
The green band is the pH both tolerate.

Size to scale

Tiger barb · 3 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

Tiger barbPencilfish
Temperature72–81 °F75–82 °F
pH6–7.55–7.5
Adult size3.0 in2.0 in
Minimum tank30 gal15 gal
TemperamentSemi-aggressivePeaceful
Swims atMiddleMiddle
GroupGroups of 6+Groups of 6+
DietOmnivoreOmnivore

Better tank mates for tiger barbs

All tiger barb tank mates

Better tank mates for pencilfish

All pencilfish tank mates

Questions

Can tiger barbs live with pencilfish?

Yes. Tiger barbs and pencilfish get along in the same tank. Both are fine at 75–81°F. Plan on at least 30 gal.

What temperature suits both tiger barbs and pencilfish?

75–81 °F. Tiger barbs need 72–81 °F, pencilfish need 75–82 °F.

What size tank do tiger barbs and pencilfish need together?

At least 30 gal, set by the tiger barb. Add space for each extra fish.