Can harlequin rasboras live with hatchetfish?

Verdict
Yes

Yes, harlequin rasboras and hatchetfish can live together. Both are fine at 75–80°F. Plan on at least 20 gal.

Harlequin rasboraHarlequin rasbora72–80°F · pH 6–7.5 HatchetfishHatchetfish75–81°F · pH 5.5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–80°Harlequin rasbora 72–80°Hatchetfish 75–81°
The green band is the temperature range both can live in.
456789Both: 6–7.5Harlequin rasbora 6–7.5Hatchetfish 5.5–7.5
The green band is the pH both tolerate.

Size to scale

Harlequin rasbora · 2 inHatchetfish · 1.5 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 rasboraHatchetfish
Temperature72–80 °F75–81 °F
pH6–7.55.5–7.5
Adult size2.0 in1.5 in
Minimum tank10 gal20 gal
TemperamentPeacefulPeaceful
Swims atMiddleTop
GroupGroups of 6+Groups of 6+
DietOmnivoreCarnivore

Better tank mates for harlequin rasboras

All harlequin rasbora tank mates

Better tank mates for hatchetfish

All hatchetfish tank mates

Questions

Can harlequin rasboras live with hatchetfish?

Yes, harlequin rasboras and hatchetfish can live together. Both are fine at 75–80°F. Plan on at least 20 gal.

What temperature suits both harlequin rasboras and hatchetfish?

75–80 °F. Harlequin rasboras need 72–80 °F, hatchetfish need 75–81 °F.

What size tank do harlequin rasboras and hatchetfish need together?

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