Copper Harlequin
Copper Harlequin

Copper Harlequin

Trigonostigma espei
SynonymsRasbora heteromorpha espei, Rasbora espei
DistributionCambodia, Laos, Thailand & Vietnam.
Sexual DimorphismMature females fuller bodied.
Maximum Size3cm (1.2”)
Water ParametersSoft & slightly acidic is best long-term. pH: 5.5-7.0, dH: up to 15 degrees.
Temperature23-28 deg C (73-82 deg F)

The Copper Harlequin is a small, peaceful, and colourful species ideally suited to quieter community aquariums. As a tightly shoaling species, these fish are best maintained in groups of 10 or more. The natural habitats of this species are blackwater marshes, ponds, pools and swamps that are quite still and inundated with abundant vegetation. This type of habitat should be replicated in the home aquarium if you wish to see these fish at their best. The tank can be aquascaped with a dark substrate and background, with plenty of dense planting amid tangles of bogwood. Floating plants can help diffuse bright lighting. Water circulation and filtration should be gentle but efficient. Suitable for housing alongside other small peaceful fish. Large, active fish will make them nervous, so choose tankmates with care. Similar in appearance to Trigonostigma hengeli and T. heteromorpha. May also be seen on sale as Lambchop Rasbora or Narrow Wedge Harlequin.


Flake, micropellets, small frozen foods such as daphnia, baby brineshrimp, cyclops and mosquito larvae.


These fish will spawn in heavily planted species-only softwater aquaria. If wishing to raise a larger number of fry, a separate shallow breeding tank should be set up with soft acidic water (pH 5.5, dH:<5 degrees), a sponge filter, a substrate of marbles and a good amount of broad-leaved plants. The underside of the leaves will be used by the fish for the process of egg laying and fertilisation, and this often begins when the first rays of morning sunshine hit the aquarium glass. The parents should be removed as soon as spawning has ceased, otherwise they will predate on the eggs. The eggs are light-sensitive, so it is important that the sides of the tank are covered in order to keep the tank in darkness and prevent the eggs from fungussing. After 24 hours, the eggs will hatch, and after a further 6 or 7 days, the wrigglers will become free-swimming. The tiny fry will require very small foods, starting with infusoria, and gradually moving on to bigger foodstuffs as they grow. Small frequent partial water changes should be carried out with much care as the fry are incredibly sensitive to changes.

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