Lambchop Rasbora (Trigonostigma espei) Care Guide
A slender, copper-orange schooling fish with a distinctive dark lambchop-shaped marking on its side. Closely related to the Harlequin Rasbora but more slender and with a brighter, more coppery colorat…
Compiled by Aquairi from published sources · Published · Updated
Overview
Trigonostigma espei is a species in the family Cyprinidae. A slender, copper-orange schooling fish with a distinctive dark lambchop-shaped marking on its side. Closely related to the Harlequin Rasbora but more slender and with a brighter, more coppery coloration. Perfect for planted nano and community tanks.
Taxonomy
- Family: Cyprinidae
- Genus: Trigonostigma
- Scientific name: Trigonostigma espei
- Other names: Espei Rasbora
- Origin: Southeast Asia, Thailand
Habitat
Native to slow-flowing forest streams and peat swamps of south-eastern Thailand and Cambodia. Inhabits soft, acidic, tannin-stained blackwater shaded by overhanging vegetation. Long confused with the related Trigonostigma heteromorpha.
Tank requirements
- Minimum tank volume: 30 L
- Temperature: 23-28 °C
- pH: 5.5-7
- GH: 1-10 °dGH
- Water flow: low
- Adult size: 2-3 cm
- Lifespan: 3-5 years
- Recommended group size: ≥ 8
- Difficulty: beginner
Diet
Classified as omnivore. Recommended feeding frequency: 2x daily. In captivity, offer a varied diet appropriate to the species — quality prepared foods supplemented with frozen or live items of suitable size.
Compatibility
- Temperament: peaceful
- Swimming level: middle
- Compatible tank mates: Neon Tetra, Corydoras, Cherry Shrimp, Otocinclus, Ember Tetra
- Avoid with: Oscar, Betta, Large Cichlids
Breeding
- Breeding strategy: egg-layer
- Breeding difficulty: intermediate
Lambchop Rasbora Breeding Guide
Overview
Trigonostigma espei is a small copper-orange cyprinid of around 2-3 cm, predominantly found in Thailand and Cambodia, with a further population on the island of Phu Quoc, Vietnam. It is named after the dark band that runs along its body like a lamb chop. The species is closely related to the harlequin rasbora and, like it, spawns in an unusual way for the family: rather than scattering eggs at random, the pair attaches eggs to the underside of broad leaves.
Sexing
Females are usually rounder-bellied and often a little larger than the slimmer, more colourful males. The dark wedge marking on the flank differs between the sexes: in males its outline is sharper and better defined, while in females it has a rounder appearance.
Breeding Setup
Use very dim lighting and either a bare base or a mesh that lets eggs pass through; plastic grass matting also works. Include broad-leaved plants such as Microsorium or Cryptocoryne, or artificial alternatives, as the spawning surface, with an optional small air-powered sponge filter.
Spawning Behavior & Trigger
Conditioned pairs adopt an inverted position beneath a broad leaf or other object as eggs and sperm are released, and the eggs are attached to the underside of that surface. Soft, acidic water of pH 5.0-6.0 and 1-5 degrees hardness at the upper end of the temperature range (toward 28 C) supports spawning.
Egg & Fry Care
Incubation usually takes between 24 and 48 hours, and the fry become free-swimming in around a week. Start them on Paramecium, then introduce Artemia nauplii and microworm once they are large enough.
Common Challenges
The very small first-feeding fry require an infusoria-grade culture, and dim conditions plus soft acidic water are needed to get eggs to develop, making this an intermediate-level project. The species itself is listed as Least Concern on the IUCN Red List, so captive breeding mainly serves the hobby rather than conservation.