How to Identify Harlequin Rasbora

To identify Harlequin Rasbora (Trigonostigma heteromorpha), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

The body is generally a coppery-orange to reddish-pink, often iridescent. The most prominent feature is a large, triangular to hatchet-shaped black patch on the posterior half of the body, extending from just behind the dorsal fin to the caudal peduncle. The fins are typically hyaline (clear) or faintly colored, sometimes with a reddish tint.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Prominent black triangular/hatchet-shaped patch on the posterior flank., Coppery-orange to reddish-pink body coloration., Relatively deep body for a small cyprinid.

Dorsal fin

Single, relatively short-based, located mid-body.

Tail fin

Forked, with rounded lobes.

Pectoral fin

Paired, small, located ventrally behind the operculum.

Distinctive fins

All fins are generally unornamented, clear to slightly tinted.

Identification Tips

1. 1

   Black Triangular Patch

   The most definitive identification feature is the large, wedge-shaped or triangular black marking on the posterior half of the body. This patch is unique in its shape and placement among similar small cyprinids.

2. 2

   Body Coloration

   The coppery-orange to reddish-pink body color, especially vibrant in healthy specimens, helps distinguish it from other rasboras that might have more silvery or yellowish hues.

3. 3

   Body Shape

   Its relatively deep and compressed body, compared to the more slender forms of some other rasbora species, is a useful characteristic.

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