Can bettas live with upside down catfish?

Verdict
Yes

Yes. Bettas and upside down catfish get along in the same tank. Both are fine at 76–79°F. Plan on at least 30 gal.

BettaBetta76–82°F · pH 6.5–7.5 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: 76–79°Betta 76–82°Upside down catfish 72–79°
The green band is the temperature range both can live in.
456789Both: 6.5–7.5Betta 6.5–7.5Upside down catfish 6–7.5
The green band is the pH both tolerate.

Size to scale

Betta · 2.5 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

BettaUpside down catfish
Temperature76–82 °F72–79 °F
pH6.5–7.56–7.5
Adult size2.5 in4.0 in
Minimum tank5 gal30 gal
TemperamentSemi-aggressivePeaceful
Swims atTopBottom
GroupOne per tankGroups of 3+
DietCarnivoreOmnivore

Better tank mates for bettas

All betta tank mates

Better tank mates for upside down catfish

All upside down catfish tank mates

Questions

Can bettas live with upside down catfish?

Yes. Bettas and upside down catfish get along in the same tank. Both are fine at 76–79°F. Plan on at least 30 gal.

What temperature suits both bettas and upside down catfish?

76–79 °F. Bettas need 76–82 °F, upside down catfish need 72–79 °F.

What size tank do bettas and upside down catfish need together?

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