Can Banded Archerfish (Brackish) and Harlequin Rasbora Live Together?

Banded Archerfish (Brackish) is a moderately assertive species (6/10), while Harlequin Rasbora is peaceful (1/10). This notable difference means Banded Archerfish (Brackish) may occasionally assert dominance over Harlequin Rasbora.

Banded Archerfish (Brackish) and Harlequin Rasbora both frequent the Top (Surface) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

Worth noting: Banded Archerfish (Brackish) is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

Both fish can tolerate a pH between 7 and 7.5. Maintaining a stable value within this band is more important than hitting an exact number.

Hardness requirements are incompatible: Banded Archerfish (Brackish) needs 15–30 dGH while Harlequin Rasbora requires 2–12 dGH.

Crucially, these species require different water types — one needs freshwater while the other requires brackish conditions. This is a hard barrier to keeping them together.

To house Banded Archerfish (Brackish) and Harlequin Rasbora together, plan for an aquarium of at least 360 litres with a minimum length of 120 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

Providing a mix of open swimming space and sheltered areas with rocks, driftwood, or plants will keep both species comfortable and allow natural behaviour.

Specific environmental needs for this combination include: Sand (Sifters), Driftwood (Digestion/Hiding), Plants - Densely covered, Leaf Litter/Blackwater. Meeting these requirements will help both species thrive.

Both species do well with moderate (standard) water movement, so a standard filtration setup rated for the tank volume should suffice.