Can siamese algae eaters live with pencilfish?

Verdict
Yes

Yes. Siamese algae eaters and pencilfish get along in the same tank. Both are fine at 75–79°F. Plan on at least 30 gal.

Siamese algae eaterSiamese algae eater75–79°F · pH 6.5–7.5 PencilfishPencilfish75–82°F · pH 5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–79°Siamese algae eater 75–79°Pencilfish 75–82°
The green band is the temperature range both can live in.
456789Both: 6.5–7.5Siamese algae eater 6.5–7.5Pencilfish 5–7.5
The green band is the pH both tolerate.

Size to scale

Siamese algae eater · 6 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

Siamese algae eaterPencilfish
Temperature75–79 °F75–82 °F
pH6.5–7.55–7.5
Adult size6.0 in2.0 in
Minimum tank30 gal15 gal
TemperamentPeacefulPeaceful
Swims atBottomMiddle
GroupAlone or in pairsGroups of 6+
DietHerbivoreOmnivore

Better tank mates for siamese algae eaters

All siamese algae eater tank mates

Better tank mates for pencilfish

All pencilfish tank mates

Questions

Can siamese algae eaters live with pencilfish?

Yes. Siamese algae eaters and pencilfish get along in the same tank. Both are fine at 75–79°F. Plan on at least 30 gal.

What temperature suits both siamese algae eaters and pencilfish?

75–79 °F. Siamese algae eaters need 75–79 °F, pencilfish need 75–82 °F.

What size tank do siamese algae eaters and pencilfish need together?

At least 30 gal, set by the siamese algae eater. Add space for each extra fish.