Can upside down catfish live with hatchetfish?

Verdict
Yes

Yes. Upside down catfish and hatchetfish make a good pair. Both are fine at 75–79°F. Plan on at least 30 gal.

Upside down catfishUpside down catfish72–79°F · pH 6–7.5 HatchetfishHatchetfish75–81°F · pH 5.5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–79°Upside down catfish 72–79°Hatchetfish 75–81°
The green band is the temperature range both can live in.
456789Both: 6–7.5Upside down catfish 6–7.5Hatchetfish 5.5–7.5
The green band is the pH both tolerate.

Size to scale

Upside down catfish · 4 inHatchetfish · 1.5 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

Upside down catfishHatchetfish
Temperature72–79 °F75–81 °F
pH6–7.55.5–7.5
Adult size4.0 in1.5 in
Minimum tank30 gal20 gal
TemperamentPeacefulPeaceful
Swims atBottomTop
GroupGroups of 3+Groups of 6+
DietOmnivoreCarnivore

Better tank mates for upside down catfish

All upside down catfish tank mates

Better tank mates for hatchetfish

All hatchetfish tank mates

Questions

Can upside down catfish live with hatchetfish?

Yes. Upside down catfish and hatchetfish make a good pair. Both are fine at 75–79°F. Plan on at least 30 gal.

What temperature suits both upside down catfish and hatchetfish?

75–79 °F. Upside down catfish need 72–79 °F, hatchetfish need 75–81 °F.

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

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