Maximum size : 3 cm

Lambchop Rasbora - Trigonostigma espei : Complete Fish Profile & Care Guide

Table of contents


The Lambchop Rasbora (Trigonostigma espei) is a fascinating fish that any aquarium enthusiast would love to have in their collection. These fish are known for their friendly and active nature and are an excellent addition to any peaceful community tank. They are also hardy and low maintenance, making them an excellent choice for beginners. Keeping them in groups of 8 to 10 individuals is recommended to maintain their species' companionship and promote their well-being. Regarding tankmates, Lambchop Rasboras get along well with other calm community fish and peaceful bottom-dwelling species. However, larger or more aggressive fish may not be the best company for them. 

To optimize the visual presentation of these fish within the aquarium, meticulous aquascaping considerations come into play. Employing a dark-hued substrate and backdrop forms a cohesive visual canvas, accentuating their finest attributes. Strategically integrating copious and luxuriant plantings amid intricately arranged bogwood structures serves to emulate their natural habitat, fostering an enriched environment.

 Floating plant species can be judiciously employed to temper intense lighting conditions, casting a more diffuse luminous ambience. As regards the aquatic ecosystem's mechanics, achieving a balance is paramount, with an emphasis on gentle yet efficient water circulation and filtration methodologies. Additionally, a tight-fitting lid is necessary as these fish may jump if startled or excited. 

The Lambchop Rasbora boasts a unique bronze colour with a pinkish blush that appears increasingly reflective approaching the lateral line. Their black lambchop-shaped marking along their side is a distinguishing feature, and their body colour may vary slightly depending on the area they come from. Owning these fish is a rewarding experience for any aquarium hobbyist.

Lambchop Rasbora Photos

Sexual Dimorphism

Distinguishing between male and female Lambchop Rasboras is a relatively straightforward task. Mature males exhibit vivid colours and are comparatively slender, while their dark, wedge-shaped markings are well-defined and sharply outlined. Conversely, females possess a fuller belly and a more elevated body, and their markings are less prominent than those of their male counterparts.

Quick Facts

Scientific NameTrigonostigma espei
Year Described1967
Other NamesEspei Rasbora, False Harlequin Rasbora, Narrow Wedge Harlequin, Slim Harlequin
OriginsThailand , Cambodia
Max Size3 cm
Aquarium LevelAll Levels
Best kept asGroups 8+
Diet & FeedingOmnivore
ReproductionEgg Depositor
LifespanUp to 5 Years

Water Parameters

Water TypeFreshwater
pH 6.0 - 8.0
GH 1 - 15
TDS 18 - 179
Ideal Temperature
73 - 80
22 - 26

Natural Habitat

The Lambchop Rasbora is a fascinating fish that can be found in two main populations: one in the Gulf of Thailand's eastern slopes and the other in Cambodia in Southeast Asia. Recently, a new population of these fish has been discovered on the nearby island of Phu Quoc in Vietnam. These fish prefer to inhabit slow-flowing waters, such as streams, ponds, pools, marshes, and swamps, where submerged aquatic plants grow thickly. The water in their natural habitat can sometimes appear stained yellowish-brown due to the release of chemicals and tannins from decomposing organic material. The substrate in these areas is usually scattered with fallen twigs, leaves, and branches, providing the perfect environment for these fish to thrive.


Lambchop Rasboras can be challenging to breed, but with proper care, you may be successful in spawning them. Providing a well-maintained aquarium with dense planting is crucial. In a controlled breeding environment, it is recommended to condition one or two pairs with small servings of live or frozen foods for about four weeks. A dimly lit breeding tank with soft, slightly acidic water and a higher temperature range is ideal. Filtration is not mandatory, but you can add an air-powered sponge filter or peat filtration. The fish require artificial or live broad-leaved plants for the eggs to attach, and a spawning mop can also be added.

Spawning typically occurs the following morning after placing one or two pairs into the breeding tank. First, the male will lead the female to his selected location, usually on the broad-leaved plant's underside. Then, the male will perform a courtship dance, and spawning takes place under the plant leaves, with the partner swimming upside down. After spawning has occurred, remove the parents, as they will consume the eggs. Next, darken the tank and reduce the water level, ensuring the eggs are below the water's surface.

The fry will usually hatch around 24 hours later and should be fed infusoria-type foods. Seven to 14 days after that, the fry will become free swimming, and then you can feed them baby brine shrimp and tiny flake foods. Overall, Lambchop Rasboras are somewhat challenging to breed, but with proper care and attention to their spawning methods, you can achieve success.

Diet & feeding

To maintain optimal health and colouration of Lambchop Rasboras, it is recommended to supplement their diet with live and frozen foods such as daphnia, artemia, and bloodworm. While they are not picky eaters and will consume good quality flakes and granules, offering a variety of small live and frozen foods will promote their best condition. These fish will also appreciate occasional treats such as blanched spinach or lettuce. It is essential to feed them several times a day, but it is recommended to offer them only the amount they can consume in under three minutes to prevent overfeeding and water quality issues.

Other Rasboras of interest