Can kuhli loaches live with harlequin rasboras?

Verdict
Yes

Yes. Kuhli loaches and harlequin rasboras get along in the same tank. Both are fine at 75–80°F. Plan on at least 20 gal.

Kuhli loachKuhli loach75–86°F · pH 5.5–7 Harlequin rasboraHarlequin rasbora72–80°F · pH 6–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–80°Kuhli loach 75–86°Harlequin rasbora 72–80°
The green band is the temperature range both can live in.
456789Both: 6–7Kuhli loach 5.5–7Harlequin rasbora 6–7.5
The green band is the pH both tolerate.

Size to scale

Kuhli loach · 3.5 inHarlequin rasbora · 2 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

Kuhli loachHarlequin rasbora
Temperature75–86 °F72–80 °F
pH5.5–76–7.5
Adult size3.5 in2.0 in
Minimum tank20 gal10 gal
TemperamentPeacefulPeaceful
Swims atBottomMiddle
GroupGroups of 6+Groups of 6+
DietOmnivoreOmnivore

Better tank mates for kuhli loaches

All kuhli loach tank mates

Better tank mates for harlequin rasboras

All harlequin rasbora tank mates

Questions

Can kuhli loaches live with harlequin rasboras?

Yes. Kuhli loaches and harlequin rasboras get along in the same tank. Both are fine at 75–80°F. Plan on at least 20 gal.

What temperature suits both kuhli loaches and harlequin rasboras?

75–80 °F. Kuhli loaches need 75–86 °F, harlequin rasboras need 72–80 °F.

What size tank do kuhli loaches and harlequin rasboras need together?

At least 20 gal, set by the kuhli loach. Add space for each extra fish.