Can jack dempseys live with fancy goldfish?

Verdict
No

No. Jack dempseys and fancy goldfish should not share a tank. Fancy goldfish are coldwater animals (65–74°F); jack dempseys need 72–86°F. They overlap only at 72–74°F, the edge of both ranges.

Jack DempseyJack Dempsey72–86°F · pH 6.5–7.5 Fancy goldfishFancy goldfish65–74°F · pH 7–8

What to watch

What works

Water side by side

55°60°65°70°75°80°85°90°Both: 72–74°Jack Dempsey 72–86°Fancy goldfish 65–74°
The green band is the temperature range both can live in.
456789Both: 7–7.5Jack Dempsey 6.5–7.5Fancy goldfish 7–8
The green band is the pH both tolerate.

Size to scale

Jack Dempsey · 10 inFancy goldfish · 6 in0"2"4"6"8"10"
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

Jack DempseyFancy goldfish
Temperature72–86 °F65–74 °F
pH6.5–7.57–8
Adult size10.0 in6.0 in
Minimum tank55 gal30 gal
TemperamentAggressivePeaceful
Swims atMiddleAll levels
GroupAlone or in pairsAlone or in pairs
DietCarnivoreOmnivore

Better tank mates for jack dempseys

All jack dempsey tank mates

Better tank mates for fancy goldfish

All fancy goldfish tank mates

Questions

Can jack dempseys live with fancy goldfish?

No. Jack dempseys and fancy goldfish should not share a tank. Fancy goldfish are coldwater animals (65–74°F); jack dempseys need 72–86°F. They overlap only at 72–74°F, the edge of both ranges.

What temperature suits both jack dempseys and fancy goldfish?

72–74 °F. Jack dempseys need 72–86 °F, fancy goldfish need 65–74 °F.

What size tank do jack dempseys and fancy goldfish need together?

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