Can harlequin rasboras live with rosy barbs?

Verdict
Yes

Yes, harlequin rasboras and rosy barbs can live together. Both are fine at 72–77°F. Plan on at least 30 gal.

Harlequin rasboraHarlequin rasbora72–80°F · pH 6–7.5 Rosy barbRosy barb64–77°F · pH 6–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 72–77°Harlequin rasbora 72–80°Rosy barb 64–77°
The green band is the temperature range both can live in.
456789Both: 6–7.5Harlequin rasbora 6–7.5Rosy barb 6–7.5
The green band is the pH both tolerate.

Size to scale

Harlequin rasbora · 2 inRosy barb · 4 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

Harlequin rasboraRosy barb
Temperature72–80 °F64–77 °F
pH6–7.56–7.5
Adult size2.0 in4.0 in
Minimum tank10 gal30 gal
TemperamentPeacefulSemi-aggressive
Swims atMiddleMiddle
GroupGroups of 6+Groups of 6+
DietOmnivoreOmnivore

Better tank mates for harlequin rasboras

All harlequin rasbora tank mates

Better tank mates for rosy barbs

All rosy barb tank mates

Questions

Can harlequin rasboras live with rosy barbs?

Yes, harlequin rasboras and rosy barbs can live together. Both are fine at 72–77°F. Plan on at least 30 gal.

What temperature suits both harlequin rasboras and rosy barbs?

72–77 °F. Harlequin rasboras need 72–80 °F, rosy barbs need 64–77 °F.

What size tank do harlequin rasboras and rosy barbs need together?

At least 30 gal, set by the rosy barb. Add space for each extra fish.