Can red tail sharks live with electric blue acaras?

Verdict
Yes

Yes. Red tail sharks and electric blue acaras make a good pair. 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 Electric blue acaraElectric blue acara72–82°F · pH 6.5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 72–79°Red tail shark 72–79°Electric blue acara 72–82°
The green band is the temperature range both can live in.
456789Both: 6.5–7.5Red tail shark 6.5–7.5Electric blue acara 6.5–7.5
The green band is the pH both tolerate.

Size to scale

Red tail shark · 5 inElectric blue acara · 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

Red tail sharkElectric blue acara
Temperature72–79 °F72–82 °F
pH6.5–7.56.5–7.5
Adult size5.0 in6.0 in
Minimum tank55 gal30 gal
TemperamentSemi-aggressiveSemi-aggressive
Swims atBottomMiddle
GroupOne per tankAlone or in pairs
DietOmnivoreOmnivore

Better tank mates for red tail sharks

All red tail shark tank mates

Better tank mates for electric blue acaras

All electric blue acara tank mates

Questions

Can red tail sharks live with electric blue acaras?

Yes. Red tail sharks and electric blue acaras make a good pair. Both are fine at 72–79°F. Plan on at least 55 gal.

What temperature suits both red tail sharks and electric blue acaras?

72–79 °F. Red tail sharks need 72–79 °F, electric blue acaras need 72–82 °F.

What size tank do red tail sharks and electric blue acaras need together?

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