Harlequin Rasbora - Trigonostigma heteromorpha 1-2cm

The Trigonostigma heteromorpha, commonly known as the Harlequin Rasbora, is a classic and enduringly popular freshwater fish native to the peat swamp forests and streams of Southeast Asia, particularly Thailand, Malaysia, and Singapore.

These striking cyprinids are instantly recognisable by the distinctive black triangular patch—often described as a "pork chop" shape—that adorns the rear half of their body, contrasting beautifully against a copper-orange to pinkish-red background. Growing to a modest 4-5 centimetres in length, they possess a deep, lozenge-shaped body that shimmers under aquarium lighting.

Their vibrant colouration and tight schooling behaviour make them a captivating focal point in any community aquarium, especially when kept in large groups against lush green planting.

As highly social creatures, Harlequin Rasboras must be kept in shoals of at least 6-8 individuals to feel secure and display their best natural behaviour; solitary specimens often become timid and pale.

They occupy the middle to upper water levels and are exceptionally peaceful, making them ideal residents for community tanks alongside other small, gentle species such as tetras, Corydoras, dwarf gouramis, and other rasboras.

Omnivorous and unfussy, they thrive on high-quality flake foods and micro-pellets, supplemented with small live or frozen treats such as daphnia, brine shrimp, and bloodworms to enhance their red colouration. They appreciate a well-planted aquarium with dimmed lighting or floating plants to replicate their natural blackwater habitat, along with open swimming space.

With proper care including regular water changes and stable, slightly acidic to neutral water conditions, Harlequin Rasboras typically live 5-6 years, making them robust, colourful, and beginner-friendly additions to any peaceful setup.