Harlequin Rasbora Care Sheet
Trigonostigma heteromorpha
One of the most popular schooling fish in the hobby. The distinctive black triangular patch on a copper body makes them instantly recognizable. Peaceful and easy to keep.
72–81°F
6–7.5
10 gallons
5–8 years
1.5–2 inches (4–5 cm)
8+ (looks best in larger schools)
Moderate-difficult. Deposit eggs on the underside of broad leaves (like Cryptocoryne). Need very soft, acidic water to trigger spawning.
Diet & Feeding
Omnivore — flakes, micro pellets, frozen/freeze-dried foods. Small mouth — needs appropriately sized food.
Natural Habitat
Native to peat swamp forests in Southeast Asia (Malaysia, Singapore, Thailand). Prefer soft, acidic, tannin-stained water.
Care Tips
Keep in schools of 8+ for the best display — they school tightly when they feel secure
Thrive in planted tanks with driftwood and tannins
Peaceful with everything — ideal dither fish for shy species
Hardy once acclimated but sensitive to sudden parameter changes
Indian almond leaves replicate their natural tannin-rich water