Can bolivian rams live with cardinal tetras?

Verdict
Yes

Yes. Bolivian rams and cardinal tetras make a good pair. Both are fine at 76–79°F. Plan on at least 20 gal.

Bolivian ramBolivian ram72–79°F · pH 6–7.5 Cardinal tetraCardinal tetra76–84°F · pH 4.6–7

Why it works

Water side by side

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

Size to scale

Bolivian ram · 3 inCardinal tetra · 2 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

Bolivian ramCardinal tetra
Temperature72–79 °F76–84 °F
pH6–7.54.6–7
Adult size3.0 in2.0 in
Minimum tank20 gal20 gal
TemperamentPeacefulPeaceful
Swims atBottomMiddle
GroupAlone or in pairsGroups of 6+
DietOmnivoreOmnivore

Better tank mates for bolivian rams

All bolivian ram tank mates

Better tank mates for cardinal tetras

All cardinal tetra tank mates

Questions

Can bolivian rams live with cardinal tetras?

Yes. Bolivian rams and cardinal tetras make a good pair. Both are fine at 76–79°F. Plan on at least 20 gal.

What temperature suits both bolivian rams and cardinal tetras?

76–79 °F. Bolivian rams need 72–79 °F, cardinal tetras need 76–84 °F.

What size tank do bolivian rams and cardinal tetras need together?

At least 20 gal, set by the bolivian ram. Add space for each extra fish.