Can fancy goldfish live with platies?

Verdict
Yes

Yes. Fancy goldfish and platies make a good pair. Both are fine at 70–74°F. Plan on at least 30 gal.

Fancy goldfishFancy goldfish65–74°F · pH 7–8 PlatyPlaty70–80°F · pH 7–8.2

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 70–74°Fancy goldfish 65–74°Platy 70–80°
The green band is the temperature range both can live in.
456789Both: 7–8Fancy goldfish 7–8Platy 7–8.2
The green band is the pH both tolerate.

Size to scale

Fancy goldfish · 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

Fancy goldfishPlaty
Temperature65–74 °F70–80 °F
pH7–87–8.2
Adult size6.0 in2.5 in
Minimum tank30 gal10 gal
TemperamentPeacefulPeaceful
Swims atAll levelsMiddle
GroupAlone or in pairsGroups of 3+
DietOmnivoreOmnivore

Better tank mates for fancy goldfish

All fancy goldfish tank mates

Better tank mates for platies

All platy tank mates

Questions

Can fancy goldfish live with platies?

Yes. Fancy goldfish and platies make a good pair. Both are fine at 70–74°F. Plan on at least 30 gal.

What temperature suits both fancy goldfish and platies?

70–74 °F. Fancy goldfish need 65–74 °F, platies need 70–80 °F.

What size tank do fancy goldfish and platies need together?

At least 30 gal, set by the fancy goldfish. Add space for each extra fish.