Can red tail sharks live with serpae tetras?

Verdict
Yes

Yes. Red tail sharks and serpae tetras get along in the same tank. Both are fine at 72–79°F. Plan on at least 55 gal.

Red tail sharkRed tail shark72–79°F · pH 6.5–7.5 Serpae tetraSerpae tetra72–79°F · pH 6–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 72–79°Red tail shark 72–79°Serpae tetra 72–79°
The green band is the temperature range both can live in.
456789Both: 6.5–7.5Red tail shark 6.5–7.5Serpae tetra 6–7.5
The green band is the pH both tolerate.

Size to scale

Red tail shark · 5 inSerpae tetra · 1.75 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

Red tail sharkSerpae tetra
Temperature72–79 °F72–79 °F
pH6.5–7.56–7.5
Adult size5.0 in1.75 in
Minimum tank55 gal20 gal
TemperamentSemi-aggressiveSemi-aggressive
Swims atBottomMiddle
GroupOne per tankGroups of 6+
DietOmnivoreOmnivore

Better tank mates for red tail sharks

All red tail shark tank mates

Better tank mates for serpae tetras

All serpae tetra tank mates

Questions

Can red tail sharks live with serpae tetras?

Yes. Red tail sharks and serpae tetras get along in the same tank. Both are fine at 72–79°F. Plan on at least 55 gal.

What temperature suits both red tail sharks and serpae tetras?

72–79 °F. Red tail sharks need 72–79 °F, serpae tetras need 72–79 °F.

What size tank do red tail sharks and serpae tetras need together?

At least 55 gal, set by the red tail shark. Add space for each extra fish.