Can bichirs live with cardinal tetras?

Verdict
No

No. Bichirs and cardinal tetras should not share a tank. An adult bichir eats fish that fit in its mouth, and at 2 inches cardinal tetras do.

BichirBichir72–82°F · pH 6.5–7.5 Cardinal tetraCardinal tetra76–84°F · pH 4.6–7

What to watch

What works

Water side by side

55°60°65°70°75°80°85°90°Both: 76–82°Bichir 72–82°Cardinal tetra 76–84°
The green band is the temperature range both can live in.
456789Both: 6.5–7Bichir 6.5–7.5Cardinal tetra 4.6–7
The green band is the pH both tolerate.

Size to scale

Bichir · 12 inCardinal tetra · 2 in0"2"4"6"8"10"12"
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

BichirCardinal tetra
Temperature72–82 °F76–84 °F
pH6.5–7.54.6–7
Adult size12.0 in2.0 in
Minimum tank75 gal20 gal
TemperamentSemi-aggressivePeaceful
Swims atBottomMiddle
GroupAlone or in pairsGroups of 6+
DietCarnivoreOmnivore

Better tank mates for bichirs

All bichir tank mates

Better tank mates for cardinal tetras

All cardinal tetra tank mates

Questions

Can bichirs live with cardinal tetras?

No. Bichirs and cardinal tetras should not share a tank. An adult bichir eats fish that fit in its mouth, and at 2 inches cardinal tetras do.

What temperature suits both bichirs and cardinal tetras?

76–82 °F. Bichirs need 72–82 °F, cardinal tetras need 76–84 °F.

What size tank do bichirs and cardinal tetras need together?

At least 75 gal, set by the bichir. Add space for each extra fish.