Can jack dempseys live with harlequin rasboras?

Verdict

No. Jack dempseys and harlequin rasboras should not share a tank. An adult jack dempsey eats fish that fit in its mouth, and at 2 inches harlequin rasboras do.

Jack Dempsey72–86°F · pH 6.5–7.5

Harlequin rasbora72–80°F · pH 6–7.5

What to watch

Deal breakerAn adult jack dempsey eats fish that fit in its mouth, and at 2 inches harlequin rasboras do.
Deal breakerJack dempseys are aggressive and will bully peaceful harlequin rasboras.

What works

Both are fine at 72–80°F.
pH 6.5–7.5 suits both.

Water side by side

The green band is the temperature range both can live in.

The green band is the pH both tolerate.

Size to scale

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

	Jack Dempsey	Harlequin rasbora
Temperature	72–86 °F	72–80 °F
pH	6.5–7.5	6–7.5
Adult size	10.0 in	2.0 in
Minimum tank	55 gal	10 gal
Temperament	Aggressive	Peaceful
Swims at	Middle	Middle
Group	Alone or in pairs	Groups of 6+
Diet	Carnivore	Omnivore

Better tank mates for jack dempseys

CrayfishYes

All jack dempsey tank mates

Better tank mates for harlequin rasboras

All harlequin rasbora tank mates

Questions

Can jack dempseys live with harlequin rasboras?

No. Jack dempseys and harlequin rasboras should not share a tank. An adult jack dempsey eats fish that fit in its mouth, and at 2 inches harlequin rasboras do.

What temperature suits both jack dempseys and harlequin rasboras?

72–80 °F. Jack dempseys need 72–86 °F, harlequin rasboras need 72–80 °F.

What size tank do jack dempseys and harlequin rasboras need together?

At least 55 gal, set by the jack dempsey. Add space for each extra fish.