Can congo tetras live with harlequin rasboras?

Verdict
Yes

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

Congo tetraCongo tetra73–82°F · pH 6–7.5 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°Congo tetra 73–82°Harlequin rasbora 72–80°
The green band is the temperature range both can live in.
456789Both: 6–7.5Congo tetra 6–7.5Harlequin rasbora 6–7.5
The green band is the pH both tolerate.

Size to scale

Congo tetra · 3 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

Congo tetraHarlequin rasbora
Temperature73–82 °F72–80 °F
pH6–7.56–7.5
Adult size3.0 in2.0 in
Minimum tank30 gal10 gal
TemperamentPeacefulPeaceful
Swims atMiddleMiddle
GroupGroups of 6+Groups of 6+
DietOmnivoreOmnivore

Better tank mates for congo tetras

All congo tetra tank mates

Better tank mates for harlequin rasboras

All harlequin rasbora tank mates

Questions

Can congo tetras live with harlequin rasboras?

Yes. Congo tetras 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 congo tetras and harlequin rasboras?

73–80 °F. Congo tetras need 73–82 °F, harlequin rasboras need 72–80 °F.

What size tank do congo tetras and harlequin rasboras need together?

At least 30 gal, set by the congo tetra. Add space for each extra fish.