Can discus live with platies?

Verdict
No

No. Discus and platies should not share a tank. No shared temperature. Discus need 82–88°F, platies need 70–80°F.

DiscusDiscus82–88°F · pH 5.5–7 PlatyPlaty70–80°F · pH 7–8.2

What to watch

Water side by side

55°60°65°70°75°80°85°90°Discus 82–88°Platy 70–80°
The ranges do not meet, so one of them would always be too warm or too cold.
456789Both: 7Discus 5.5–7Platy 7–8.2
The green band is the pH both tolerate.

Size to scale

Discus · 6 inPlaty · 2.5 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

DiscusPlaty
Temperature82–88 °F70–80 °F
pH5.5–77–8.2
Adult size6.0 in2.5 in
Minimum tank55 gal10 gal
TemperamentPeacefulPeaceful
Swims atMiddleMiddle
GroupGroups of 5+Groups of 3+
DietCarnivoreOmnivore

Better tank mates for discus

All discus tank mates

Better tank mates for platies

All platy tank mates

Questions

Can discus live with platies?

No. Discus and platies should not share a tank. No shared temperature. Discus need 82–88°F, platies need 70–80°F.

What temperature suits both discus and platies?

None. Discus need 82–88 °F and platies need 70–80 °F, so the ranges do not meet.

What size tank do discus and platies need together?

At least 55 gal, set by the discus. Add space for each extra fish.