Can congo tetras live with upside down catfish?

Verdict
Yes

Yes. Congo tetras and upside down catfish make a good pair. Both are fine at 73–79°F. Plan on at least 30 gal.

Congo tetraCongo tetra73–82°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: 73–79°Congo tetra 73–82°Upside down catfish 72–79°
The green band is the temperature range both can live in.
456789Both: 6–7.5Congo tetra 6–7.5Upside down catfish 6–7.5
The green band is the pH both tolerate.

Size to scale

Congo tetra · 3 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

Congo tetraUpside down catfish
Temperature73–82 °F72–79 °F
pH6–7.56–7.5
Adult size3.0 in4.0 in
Minimum tank30 gal30 gal
TemperamentPeacefulPeaceful
Swims atMiddleBottom
GroupGroups of 6+Groups of 3+
DietOmnivoreOmnivore

Better tank mates for congo tetras

All congo tetra tank mates

Better tank mates for upside down catfish

All upside down catfish tank mates

Questions

Can congo tetras live with upside down catfish?

Yes. Congo tetras and upside down catfish make a good pair. Both are fine at 73–79°F. Plan on at least 30 gal.

What temperature suits both congo tetras and upside down catfish?

73–79 °F. Congo tetras need 73–82 °F, upside down catfish need 72–79 °F.

What size tank do congo tetras and upside down catfish need together?

At least 30 gal, set by the congo tetra. Add space for each extra fish.