Lambchop Rasbora

Trigonostigma espei is distinguished from the classic Harlequin by its more elongated, lambda-shaped black patch and slimmer profile. Found in slow, shaded streams and blackwater pools across Thailand and Cambodia, it prefers soft, acidic water enriched with botanical tannins. Males display more intense colouration and compete gently with each other, making a school in a well-planted biotope one of the hobby's understated gems.

Water: 23–28 °C, pH 6.0–7.0, soft water preferred (GH 2–10). Tank: 40 L minimum; heavily planted with leaf litter, peat filtration recommended. Feeding: Omnivore — micro pellets, small frozen foods, baby brine shrimp, fine flake. Behaviour: Peaceful, active schooler; keep 8+ for natural group behaviour. Compatibility: Excellent with small tetras, other rasboras, pygmy corys, and nano shrimp.