Can cardinal tetras live with siamese algae eaters?

Verdict
Yes

Yes, cardinal tetras and siamese algae eaters can live together. Both are fine at 76–79°F. Plan on at least 30 gal.

Cardinal tetraCardinal tetra76–84°F · pH 4.6–7 Siamese algae eaterSiamese algae eater75–79°F · pH 6.5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 76–79°Cardinal tetra 76–84°Siamese algae eater 75–79°
The green band is the temperature range both can live in.
456789Both: 6.5–7Cardinal tetra 4.6–7Siamese algae eater 6.5–7.5
The green band is the pH both tolerate.

Size to scale

Cardinal tetra · 2 inSiamese algae eater · 6 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 tetraSiamese algae eater
Temperature76–84 °F75–79 °F
pH4.6–76.5–7.5
Adult size2.0 in6.0 in
Minimum tank20 gal30 gal
TemperamentPeacefulPeaceful
Swims atMiddleBottom
GroupGroups of 6+Alone or in pairs
DietOmnivoreHerbivore

Better tank mates for cardinal tetras

All cardinal tetra tank mates

Better tank mates for siamese algae eaters

All siamese algae eater tank mates

Questions

Can cardinal tetras live with siamese algae eaters?

Yes, cardinal tetras and siamese algae eaters can live together. Both are fine at 76–79°F. Plan on at least 30 gal.

What temperature suits both cardinal tetras and siamese algae eaters?

76–79 °F. Cardinal tetras need 76–84 °F, siamese algae eaters need 75–79 °F.

What size tank do cardinal tetras and siamese algae eaters need together?

At least 30 gal, set by the siamese algae eater. Add space for each extra fish.