Can apistogramma live with pencilfish?

Verdict
Yes

Yes. Apistogramma and pencilfish get along in the same tank. Both are fine at 75–82°F. Plan on at least 20 gal.

ApistogrammaApistogramma75–84°F · pH 5–7 PencilfishPencilfish75–82°F · pH 5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–82°Apistogramma 75–84°Pencilfish 75–82°
The green band is the temperature range both can live in.
456789Both: 5–7Apistogramma 5–7Pencilfish 5–7.5
The green band is the pH both tolerate.

Size to scale

Apistogramma · 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

ApistogrammaPencilfish
Temperature75–84 °F75–82 °F
pH5–75–7.5
Adult size3.0 in2.0 in
Minimum tank20 gal15 gal
TemperamentSemi-aggressivePeaceful
Swims atBottomMiddle
GroupAlone or in pairsGroups of 6+
DietCarnivoreOmnivore

Better tank mates for apistogramma

All apistogramma tank mates

Better tank mates for pencilfish

All pencilfish tank mates

Questions

Can apistogramma live with pencilfish?

Yes. Apistogramma and pencilfish get along in the same tank. Both are fine at 75–82°F. Plan on at least 20 gal.

What temperature suits both apistogramma and pencilfish?

75–82 °F. Apistogramma need 75–84 °F, pencilfish need 75–82 °F.

What size tank do apistogramma and pencilfish need together?

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