Trigonostigma espei (Lambchop Rasbora)

21 March 2026

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The Lambchop Rasbora, scientifically known as Trigonostigma espei, is a captivating and peaceful schooling fish. Renowned for its brilliant copper-orange hues and distinctive black "lambchop" marking, this active cyprinid has become a favorite among aquascapers and nano-aquarium enthusiasts seeking a vibrant addition to their planted community tanks.

Overview

The Lambchop Rasbora (Trigonostigma espei), also known as Espe's Rasbora, is a stunning, peaceful schooling fish highly prized in the aquarium hobby. Known for its vibrant copper-orange coloration and distinct black marking, it is an ideal candidate for beautifully aquascaped planted tanks and nano community setups.

Image of espes wedge spotted danio trigonostigma rasbora espei

Distribution and Habitat

Native to Southeast Asia, specifically Thailand and Cambodia, this species inhabits slow-moving streams, pools, and swampy areas. Their natural waters are typically heavily vegetated and stained with tannins from decaying organic matter, creating a soft, acidic environment.

Description of Lambchop Rasbora

Body shape:

They possess a classic torpedo-shaped body that is slightly deep in the midsection, typical of many rasbora species, allowing for agile navigation through dense vegetation.

Color:

The base color is a striking copper, bronze, or bright orange. Their most distinguishing feature is a black, club-shaped or "lambchop" marking on the rear half of their body, which is notably thinner than that of the closely related Harlequin Rasbora.

Barbels:

Like many small cyprinids, they do not possess barbels.

Snout:

The snout is relatively short and slightly pointed, adapted for feeding on small insects and zooplankton.

Eyes:

They have proportionally large eyes, often ringed with an iridescent orange or golden hue.

Fins:

The fins are mostly translucent, though the dorsal and caudal fins can exhibit hints of yellow, orange, or red near the base.

The Tail:

The tail is distinctly forked, aiding in their quick, darting swimming movements.

Temper

The Lambchop Rasbora is exceptionally peaceful. They are non-aggressive and make excellent tank mates for other small, docile fish, shrimp, and snails.

Sociality

This is a highly social, obligate schooling fish. They should be kept in groups of at least 8 to 10 individuals. A larger school not only makes them feel secure but also encourages their most vibrant colors and natural schooling behaviors.

Activity

They are active, mid-level swimmers. They spend most of their time darting around the middle of the water column, especially in areas with open swimming space surrounded by plants.

Keeping and Caring for Lambchop Rasbora

Tank size:

A minimum tank size of 10 to 15 gallons is recommended for a small school, though a 20-gallon long tank is ideal to provide ample horizontal swimming space.

Water Parameters:

Temperature

They thrive in tropical temperatures ranging from 23-28°C (73-82°F).

pH

Slightly acidic to neutral water is best, with a pH range of 6.0 to 7.0.

Hardness

Soft water is preferred, ideally between 2 and 10 dGH.

Ammonia, Nitrite, Nitrate

Ammonia and Nitrite must be strictly maintained at 0 ppm. Nitrates should be kept below 20 ppm through regular water changes.

Lighting

Moderate to dim lighting is preferred. Floating plants can be used to diffuse bright lights and mimic their shaded natural habitat.

Water flow

A gentle to moderate water flow is ideal, simulating the slow-moving streams of their origin.

Decorations and Plants

They look and feel their best in heavily planted aquariums. Driftwood, leaf litter (like Indian Almond leaves), and dark substrates will bring out their brightest colors and provide beneficial tannins.

Diet

Lambchop Rasboras are omnivorous micro-predators. In the aquarium, they will readily accept high-quality crushed flakes and micro-pellets. Their diet should be supplemented with small live or frozen foods such as daphnia, baby brine shrimp, and bloodworms.

Some Feeding Tips

Feed them small amounts once or twice a day—only what they can consume in a couple of minutes. Because they have small mouths, ensure the food size is appropriately tiny.

Breeding

Breeding is slightly challenging but possible. They require very soft, acidic water and dim lighting to spawn. Interestingly, like other Trigonostigma species, they do not scatter eggs randomly but instead adhere them to the underside of broad-leaved plants like Cryptocoryne or Anubias. The parents should be removed after spawning to prevent egg predation.

Conclusion

The Lambchop Rasbora is a magnificent, low-maintenance fish that adds a brilliant splash of color and lively movement to the aquarium. Their peaceful demeanor and tight schooling behavior make them a top choice for aquascapers and community tank enthusiasts alike.

Fish info

Care level: Easy
Temperament: Peaceful
Adult size: 3 cm
Life expectancy: 3-5 years
Fish type: Cyprinid
Temperature : 23-28°C
pH: 6.0-7.0
Color Form: Black, Gold, Orange, Red, Silver

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