Max Size: 3cm

Lambchop Rasbora (Trigonostigma espei)

The Lambchop Rasbora is a peaceful, active and friendly fish and makes an excellent addition to any peaceful community aquarium. It would be best if you kept these fish in groups of at least 8 to 10 individuals. Even though they do not usually swim in a tight school, their species companionship is essential.

These Rasboras can be kept with many other popular community fish and do well with peaceful bottom-dwelling fish. However, they do not suffice well in the company of aggressive, large fish.

These Rasboras are very hardy and require little extra care, so they are an excellent fish for a beginning aquarist. To bring out their most desirable colours, you should use a darker substrate and make sure you provide them with plenty of plants. It would be ideal if you had a tight-fitting lid on the tank; otherwise, these fish would likely jump if startled or excited.

The Lambchop Rasbora is a small, slender fish with a distinctive bronze colour with a pinkish blush. The body colour appears to be increasingly reflective, approaching the lateral line. It can vary slightly depending on the area it comes from, with some individuals having a more intense red. Its most distinguishing feature is the black lambchop-shaped marking along its side.

Quick Facts
Scientific NameTrigonostigma espei
Other NamesFalse Harlequin Rasbora, Narrow Wedge Harlequin, Slim Harlequin
OriginsCambodia, Thailand
Aquarium LevelAll Levels
Best kept asGroups 8+
Lifespan3 - 5 years
Water Parameters
Water TypeFreshwater
PH6.0 - 8.0
GH1 - 15
TDS18 - 179
73 - 80℉
22.8 - 26.7℃

Photos of the Lambchop Rasbora

Lambchop rasbora

Natural Habitat

There appear to be two main populations where the Lambchop Rasbora occurs. One is in the Gulf of Thailand's eastern slopes, and the other is in Cambodia in Southeast Asia. More recently a population of these fish have been discovered on the nearby island of the Phu Quoc in Vietnam.

These fish inhabit slow-flowing waters of streams, ponds, pools, marshes, and swamps where submerged aquatic plants grow thickly. The water is sometimes stained a yellowish-brown colour due to the release of chemicals and tannins from decomposing organic material. The substrate is usually scattered with fallen twigs, leaves and branches.

What to feed the Lambchop Rasbora

Lambchop Rasboras are not picky eaters and will readily accept good quality flakes and granules. However, if you want them to display their best colours and condition, you should also offer them regular meals of small live and frozen foods such as daphnia, artemia and bloodworm.

These fish will also enjoy the odd treat of blanched spinach or lettuce.

It would be best to feed these Rasboras several times a day, but only offer what they can consume in under three minutes.

How to sex the Lambchop Rasbora

It is relatively easy to differentiate male from female Lambchop Rasboras. Mature males are much brighter and slimmer than the females, and there dark wedge-like markings are much sharper with a more definitive outline. In contrast, the females will have a fuller belly, and a higher body and their marking are not as apparent as that of the males.

How to breed the Lambchop Rasbora

Lambchop Rasboras are somewhat challenging to breed. However, if you keep them in a well-maintained aquarium with dense planting, you may notice some young fry showing up.

They present no parental care for the young, and their spawning methods differ slightly. Unlike other Rasboras, this fish attaches its eggs to the bottoms of broad-leaved plants or similar objects.

In a controlled spawning environment, one or two pairs should be well-conditioned with small helpings of live or frozen foods several times a day, usually for around four weeks. This will bring out the male's best colour and allow the females to fill out with eggs.

You should provide a dimly lit breeding tank and keep the water level low. The water should be very soft, slightly acidic, and the temperature needs to be towards the higher range. Filtration isn't mandatory, but you can add a small air-powered sponge filter or some peat filtration.

The fish will require artificial or live broad-leaved plants for the eggs to adhere too. You can also add a spawning mop so any eggs that do not manage to attach to the leaves have somewhere to fall out of the parents' reach.

You should then place one or two pairs into the breeding tank, and then spawning will typically occur the following morning. The male will lead the female to his selected location, usually on the broad-leaved plant's underside. The male will then perform a courtship dance, and spawning takes place under the plant leaves, with the partner's swimming upside down.

Once spawning has occurred, you should then remove the parents as they will consume the eggs. After they have been removed, you should then darken the tank and reduced the water level making sure the eggs are below the water's surface.

The fry will usually hatch around 24 hours later at this time you should feed them with infusoria type foods. 7 to 14 days after that the fry will become free swimming, and then you can feed them on baby brine shrimp and tiny flake foods.

Other Rasboras of interest

Black Line Rasbora(Rasbora borapetensis)
Chilli Rasbora(Boraras Brigittae)
Clown Rasbora(Rasbora kalochroma)
Dwarf Rasbora(Boraras maculatus)
Emerald Eye Rasbora(Brevibora dorsiocellata)
Exclamation Point Rasbora(Boraras urophthalmoides)
View all Rasboras
Date Added: 06/01/2021 - Updated: 19/01/2022 14:16:58