Can bristlenose plecos live with cardinal tetras?

Verdict
Yes

Yes. Bristlenose plecos and cardinal tetras get along in the same tank. Both are fine at 76–81°F. Plan on at least 30 gal.

Bristlenose plecoBristlenose pleco73–81°F · pH 6.5–7.5 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: 76–81°Bristlenose pleco 73–81°Cardinal tetra 76–84°
The green band is the temperature range both can live in.
456789Both: 6.5–7Bristlenose pleco 6.5–7.5Cardinal tetra 4.6–7
The green band is the pH both tolerate.

Size to scale

Bristlenose pleco · 5 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

Bristlenose plecoCardinal tetra
Temperature73–81 °F76–84 °F
pH6.5–7.54.6–7
Adult size5.0 in2.0 in
Minimum tank30 gal20 gal
TemperamentPeacefulPeaceful
Swims atBottomMiddle
GroupAlone or in pairsGroups of 6+
DietHerbivoreOmnivore

Better tank mates for bristlenose plecos

All bristlenose pleco tank mates

Better tank mates for cardinal tetras

All cardinal tetra tank mates

Questions

Can bristlenose plecos live with cardinal tetras?

Yes. Bristlenose plecos and cardinal tetras get along in the same tank. Both are fine at 76–81°F. Plan on at least 30 gal.

What temperature suits both bristlenose plecos and cardinal tetras?

76–81 °F. Bristlenose plecos need 73–81 °F, cardinal tetras need 76–84 °F.

What size tank do bristlenose plecos and cardinal tetras need together?

At least 30 gal, set by the bristlenose pleco. Add space for each extra fish.