Can red tail sharks live with silver dollars?

Verdict
Yes

Yes. Red tail sharks and silver dollars get along in the same tank. Both are fine at 75–79°F. Plan on at least 75 gal.

Red tail sharkRed tail shark72–79°F · pH 6.5–7.5 Silver dollarSilver dollar75–82°F · pH 5–7

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–79°Red tail shark 72–79°Silver dollar 75–82°
The green band is the temperature range both can live in.
456789Both: 6.5–7Red tail shark 6.5–7.5Silver dollar 5–7
The green band is the pH both tolerate.

Size to scale

Red tail shark · 5 inSilver dollar · 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 sharkSilver dollar
Temperature72–79 °F75–82 °F
pH6.5–7.55–7
Adult size5.0 in6.0 in
Minimum tank55 gal75 gal
TemperamentSemi-aggressivePeaceful
Swims atBottomMiddle
GroupOne per tankGroups of 5+
DietOmnivoreHerbivore

Better tank mates for red tail sharks

All red tail shark tank mates

Better tank mates for silver dollars

All silver dollar tank mates

Questions

Can red tail sharks live with silver dollars?

Yes. Red tail sharks and silver dollars get along in the same tank. Both are fine at 75–79°F. Plan on at least 75 gal.

What temperature suits both red tail sharks and silver dollars?

75–79 °F. Red tail sharks need 72–79 °F, silver dollars need 75–82 °F.

What size tank do red tail sharks and silver dollars need together?

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