Can blue gouramis live with pencilfish?

Verdict
Yes

Yes. Blue gouramis and pencilfish get along in the same tank. Both are fine at 75–82°F. Plan on at least 30 gal.

Blue gouramiBlue gourami72–82°F · pH 6–8 PencilfishPencilfish75–82°F · pH 5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–82°Blue gourami 72–82°Pencilfish 75–82°
The green band is the temperature range both can live in.
456789Both: 6–7.5Blue gourami 6–8Pencilfish 5–7.5
The green band is the pH both tolerate.

Size to scale

Blue gourami · 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

Blue gouramiPencilfish
Temperature72–82 °F75–82 °F
pH6–85–7.5
Adult size5.0 in2.0 in
Minimum tank30 gal15 gal
TemperamentSemi-aggressivePeaceful
Swims atTopMiddle
GroupAlone or in pairsGroups of 6+
DietOmnivoreOmnivore

Better tank mates for blue gouramis

All blue gourami tank mates

Better tank mates for pencilfish

All pencilfish tank mates

Questions

Can blue gouramis live with pencilfish?

Yes. Blue gouramis and pencilfish get along in the same tank. Both are fine at 75–82°F. Plan on at least 30 gal.

What temperature suits both blue gouramis and pencilfish?

75–82 °F. Blue gouramis need 72–82 °F, pencilfish need 75–82 °F.

What size tank do blue gouramis and pencilfish need together?

At least 30 gal, set by the blue gourami. Add space for each extra fish.