Can serpae tetras live with upside down catfish?

Verdict
Yes

Yes. Serpae tetras and upside down catfish get along in the same tank. Both are fine at 72–79°F. Plan on at least 30 gal.

Serpae tetraSerpae tetra72–79°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: 72–79°Serpae tetra 72–79°Upside down catfish 72–79°
The green band is the temperature range both can live in.
456789Both: 6–7.5Serpae tetra 6–7.5Upside down catfish 6–7.5
The green band is the pH both tolerate.

Size to scale

Serpae tetra · 1.75 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

Serpae tetraUpside down catfish
Temperature72–79 °F72–79 °F
pH6–7.56–7.5
Adult size1.75 in4.0 in
Minimum tank20 gal30 gal
TemperamentSemi-aggressivePeaceful
Swims atMiddleBottom
GroupGroups of 6+Groups of 3+
DietOmnivoreOmnivore

Better tank mates for serpae tetras

All serpae tetra tank mates

Better tank mates for upside down catfish

All upside down catfish tank mates

Questions

Can serpae tetras live with upside down catfish?

Yes. Serpae tetras and upside down catfish get along in the same tank. Both are fine at 72–79°F. Plan on at least 30 gal.

What temperature suits both serpae tetras and upside down catfish?

72–79 °F. Serpae tetras need 72–79 °F, upside down catfish need 72–79 °F.

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

At least 30 gal, set by the upside down catfish. Add space for each extra fish.