Can pearl gouramis live with upside down catfish?

Verdict
Yes

Yes. Pearl gouramis and upside down catfish make a good pair. Both are fine at 77–79°F. Plan on at least 30 gal.

Pearl gouramiPearl gourami77–82°F · pH 6–7.5 Upside down catfishUpside down catfish72–79°F · pH 6–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 77–79°Pearl gourami 77–82°Upside down catfish 72–79°
The green band is the temperature range both can live in.
456789Both: 6–7.5Pearl gourami 6–7.5Upside down catfish 6–7.5
The green band is the pH both tolerate.

Size to scale

Pearl gourami · 5 inUpside down catfish · 4 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

Pearl gouramiUpside down catfish
Temperature77–82 °F72–79 °F
pH6–7.56–7.5
Adult size5.0 in4.0 in
Minimum tank30 gal30 gal
TemperamentPeacefulPeaceful
Swims atTopBottom
GroupAlone or in pairsGroups of 3+
DietOmnivoreOmnivore

Better tank mates for pearl gouramis

All pearl gourami tank mates

Better tank mates for upside down catfish

All upside down catfish tank mates

Questions

Can pearl gouramis live with upside down catfish?

Yes. Pearl gouramis and upside down catfish make a good pair. Both are fine at 77–79°F. Plan on at least 30 gal.

What temperature suits both pearl gouramis and upside down catfish?

77–79 °F. Pearl gouramis need 77–82 °F, upside down catfish need 72–79 °F.

What size tank do pearl gouramis and upside down catfish need together?

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