Can rainbow sharks live with fancy goldfish?

Verdict
No

No. Rainbow sharks and fancy goldfish should not share a tank. Fancy goldfish are coldwater animals (65–74°F); rainbow sharks need 72–80°F. They overlap only at 72–74°F, the edge of both ranges.

Rainbow sharkRainbow shark72–80°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°Rainbow shark 72–80°Fancy goldfish 65–74°
The green band is the temperature range both can live in.
456789Both: 7–7.5Rainbow shark 6.5–7.5Fancy goldfish 7–8
The green band is the pH both tolerate.

Size to scale

Rainbow shark · 6 inFancy goldfish · 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

Rainbow sharkFancy goldfish
Temperature72–80 °F65–74 °F
pH6.5–7.57–8
Adult size6.0 in6.0 in
Minimum tank55 gal30 gal
TemperamentSemi-aggressivePeaceful
Swims atBottomAll levels
GroupOne per tankAlone or in pairs
DietOmnivoreOmnivore

Better tank mates for rainbow sharks

All rainbow shark tank mates

Better tank mates for fancy goldfish

All fancy goldfish tank mates

Questions

Can rainbow sharks live with fancy goldfish?

No. Rainbow sharks and fancy goldfish should not share a tank. Fancy goldfish are coldwater animals (65–74°F); rainbow sharks need 72–80°F. They overlap only at 72–74°F, the edge of both ranges.

What temperature suits both rainbow sharks and fancy goldfish?

72–74 °F. Rainbow sharks need 72–80 °F, fancy goldfish need 65–74 °F.

What size tank do rainbow sharks and fancy goldfish need together?

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