Can assassin snails live with upside down catfish?

Verdict
Yes

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

Assassin snailAssassin snail75–80°F · pH 7–8 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: 75–79°Assassin snail 75–80°Upside down catfish 72–79°
The green band is the temperature range both can live in.
456789Both: 7–7.5Assassin snail 7–8Upside down catfish 6–7.5
The green band is the pH both tolerate.

Size to scale

Assassin snail · 1 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

Assassin snailUpside down catfish
Temperature75–80 °F72–79 °F
pH7–86–7.5
Adult size1.0 in4.0 in
Minimum tank5 gal30 gal
TemperamentPeacefulPeaceful
Swims atBottomBottom
GroupAlone or in pairsGroups of 3+
DietCarnivoreOmnivore

Better tank mates for assassin snails

All assassin snail tank mates

Better tank mates for upside down catfish

All upside down catfish tank mates

Questions

Can assassin snails live with upside down catfish?

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

What temperature suits both assassin snails and upside down catfish?

75–79 °F. Assassin snails need 75–80 °F, upside down catfish need 72–79 °F.

What size tank do assassin snails and upside down catfish need together?

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