Can paradise fish live with pencilfish?

Verdict
Yes

Yes, paradise fish and pencilfish can live together. Both are fine at 75–79°F. Plan on at least 20 gal.

Paradise fishParadise fish61–79°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: 75–79°Paradise fish 61–79°Pencilfish 75–82°
The green band is the temperature range both can live in.
456789Both: 6–7.5Paradise fish 6–8Pencilfish 5–7.5
The green band is the pH both tolerate.

Size to scale

Paradise fish · 3.5 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

Paradise fishPencilfish
Temperature61–79 °F75–82 °F
pH6–85–7.5
Adult size3.5 in2.0 in
Minimum tank20 gal15 gal
TemperamentSemi-aggressivePeaceful
Swims atTopMiddle
GroupOne per tankGroups of 6+
DietOmnivoreOmnivore

Better tank mates for paradise fish

All paradise fish tank mates

Better tank mates for pencilfish

All pencilfish tank mates

Questions

Can paradise fish live with pencilfish?

Yes, paradise fish and pencilfish can live together. Both are fine at 75–79°F. Plan on at least 20 gal.

What temperature suits both paradise fish and pencilfish?

75–79 °F. Paradise fish need 61–79 °F, pencilfish need 75–82 °F.

What size tank do paradise fish and pencilfish need together?

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