Can cardinal tetras live with paradise fish?

Verdict
Yes

Yes. Cardinal tetras and paradise fish 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 Paradise fishParadise fish61–79°F · pH 6–8

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 76–79°Cardinal tetra 76–84°Paradise fish 61–79°
The green band is the temperature range both can live in.
456789Both: 6–7Cardinal tetra 4.6–7Paradise fish 6–8
The green band is the pH both tolerate.

Size to scale

Cardinal tetra · 2 inParadise fish · 3.5 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

Cardinal tetraParadise fish
Temperature76–84 °F61–79 °F
pH4.6–76–8
Adult size2.0 in3.5 in
Minimum tank20 gal20 gal
TemperamentPeacefulSemi-aggressive
Swims atMiddleTop
GroupGroups of 6+One per tank
DietOmnivoreOmnivore

Better tank mates for cardinal tetras

All cardinal tetra tank mates

Better tank mates for paradise fish

All paradise fish tank mates

Questions

Can cardinal tetras live with paradise fish?

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

What temperature suits both cardinal tetras and paradise fish?

76–79 °F. Cardinal tetras need 76–84 °F, paradise fish need 61–79 °F.

What size tank do cardinal tetras and paradise fish need together?

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