Can bristlenose plecos live with harlequin rasboras?

Verdict
Yes

Yes. Bristlenose plecos and harlequin rasboras get along in the same tank. Both are fine at 73–80°F. Plan on at least 30 gal.

Bristlenose plecoBristlenose pleco73–81°F · pH 6.5–7.5 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: 73–80°Bristlenose pleco 73–81°Harlequin rasbora 72–80°
The green band is the temperature range both can live in.
456789Both: 6.5–7.5Bristlenose pleco 6.5–7.5Harlequin rasbora 6–7.5
The green band is the pH both tolerate.

Size to scale

Bristlenose pleco · 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

Bristlenose plecoHarlequin rasbora
Temperature73–81 °F72–80 °F
pH6.5–7.56–7.5
Adult size5.0 in2.0 in
Minimum tank30 gal10 gal
TemperamentPeacefulPeaceful
Swims atBottomMiddle
GroupAlone or in pairsGroups of 6+
DietHerbivoreOmnivore

Better tank mates for bristlenose plecos

All bristlenose pleco tank mates

Better tank mates for harlequin rasboras

All harlequin rasbora tank mates

Questions

Can bristlenose plecos live with harlequin rasboras?

Yes. Bristlenose plecos and harlequin rasboras get along in the same tank. Both are fine at 73–80°F. Plan on at least 30 gal.

What temperature suits both bristlenose plecos and harlequin rasboras?

73–80 °F. Bristlenose plecos need 73–81 °F, harlequin rasboras need 72–80 °F.

What size tank do bristlenose plecos and harlequin rasboras need together?

At least 30 gal, set by the bristlenose pleco. Add space for each extra fish.