Harlequin Rasbora

Description

The Harlequin Rasbora (Trigonostigma heteromorpha) is a small, peaceful freshwater fish native to the slow-moving rivers, streams, and peat swamps of Southeast Asia, particularly in Thailand, Malaysia, and Sumatra. Known for its shimmering copper-orange body and distinct black triangular marking on its rear half, this species is a favorite among aquarists for its beauty and active schooling behavior.
In the wild, Harlequin Rasboras inhabit soft, acidic waters rich in tannins from decaying leaves and submerged vegetation. They are omnivorous, feeding on small invertebrates, insect larvae, and plant matter while swimming in tight schools for safety.
In aquariums, Harlequin Rasboras thrive in well-planted tanks with a soft substrate, driftwood, and plenty of swimming space. They prefer dim lighting and tannin-rich water, which enhances their coloration. As schooling fish, they should be kept in groups of at least six or more to feel secure and display their natural, synchronized swimming behavior. Their peaceful nature makes them ideal tankmates for other small, non-aggressive species like tetras, Corydoras, and dwarf gouramis.
Growing to about 4-5 cm (1.5-2 inches), Harlequin Rasboras are perfect for small to medium-sized community aquariums. Their vibrant coloration, graceful movements, and peaceful temperament make them an excellent choice for aquarists looking to add elegance and liveliness to their tank.