Can cardinal tetras live with pygmy corys?

Verdict
Yes

Yes. Cardinal tetras and pygmy corys make a good pair. Both are fine at 76–79°F. Plan on at least 20 gal.

Cardinal tetraCardinal tetra76–84°F · pH 4.6–7 Pygmy coryPygmy cory72–79°F · pH 6–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 76–79°Cardinal tetra 76–84°Pygmy cory 72–79°
The green band is the temperature range both can live in.
456789Both: 6–7Cardinal tetra 4.6–7Pygmy cory 6–7.5
The green band is the pH both tolerate.

Size to scale

Cardinal tetra · 2 inPygmy cory · 1 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

Cardinal tetraPygmy cory
Temperature76–84 °F72–79 °F
pH4.6–76–7.5
Adult size2.0 in1.0 in
Minimum tank20 gal10 gal
TemperamentPeacefulPeaceful
Swims atMiddleMiddle
GroupGroups of 6+Groups of 6+
DietOmnivoreOmnivore

Better tank mates for cardinal tetras

All cardinal tetra tank mates

Better tank mates for pygmy corys

All pygmy cory tank mates

Questions

Can cardinal tetras live with pygmy corys?

Yes. Cardinal tetras and pygmy corys make a good pair. Both are fine at 76–79°F. Plan on at least 20 gal.

What temperature suits both cardinal tetras and pygmy corys?

76–79 °F. Cardinal tetras need 76–84 °F, pygmy corys need 72–79 °F.

What size tank do cardinal tetras and pygmy corys need together?

At least 20 gal, set by the cardinal tetra. Add space for each extra fish.