Can goldfish live with harlequin rasboras?

Verdict
No

No. Goldfish and harlequin rasboras should not share a tank. Goldfish are coldwater animals (60–74°F); harlequin rasboras need 72–80°F. They overlap only at 72–74°F, the edge of both ranges.

What to watch

What works

Water side by side

55°60°65°70°75°80°85°90°Both: 72–74°Goldfish 60–74°Harlequin rasbora 72–80°
The green band is the temperature range both can live in.
456789Both: 7–7.5Goldfish 7–8Harlequin rasbora 6–7.5
The green band is the pH both tolerate.

Size to scale

Goldfish · 10 inHarlequin rasbora · 2 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

GoldfishHarlequin rasbora
Temperature60–74 °F72–80 °F
pH7–86–7.5
Adult size10.0 in2.0 in
Minimum tank40 gal10 gal
TemperamentPeacefulPeaceful
Swims atAll levelsMiddle
GroupAlone or in pairsGroups of 6+
DietOmnivoreOmnivore

Better tank mates for goldfish

All goldfish tank mates

Better tank mates for harlequin rasboras

All harlequin rasbora tank mates

Questions

Can goldfish live with harlequin rasboras?

No. Goldfish and harlequin rasboras should not share a tank. Goldfish are coldwater animals (60–74°F); harlequin rasboras need 72–80°F. They overlap only at 72–74°F, the edge of both ranges.

What temperature suits both goldfish and harlequin rasboras?

72–74 °F. Goldfish need 60–74 °F, harlequin rasboras need 72–80 °F.

What size tank do goldfish and harlequin rasboras need together?

At least 40 gal, set by the goldfish. Add space for each extra fish.