The harlequin rasbora (Trigonostigma heteromorpha) is native to the tropical waters of Southeast Asia. Its natural range includes Malaysia, Singapore, Sumatra and southern Thailand.
It is mostly found in peat swamp forest streams, small shaded waterways and shallow, slow-moving waters. In these habitats, the water is usually soft, clear and rich in vegetation. Dense aquatic plants provide important shelter, while the shaded environment creates a calm and protected habitat for this peaceful schooling fish.
