How to Identify Pacific Roosterfish

To identify Pacific Roosterfish (Nematistius pectoralis), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Silvery body with iridescent blue-green reflections dorsally, fading to white ventrally. Characterized by 7-8 dark, vertical stripes on the flanks, which can vary in intensity.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Seven greatly elongated, free-standing dorsal fin spines, which can be raised and lowered independently., A prominent, steep forehead., Large, dark, vertical stripes on the flanks.

Dorsal fin

Two dorsal fins. The first dorsal fin consists of 7 very long, filamentous spines, which are not connected by a membrane for most of their length. The second dorsal fin is much shorter, with one spine and 13-14 soft rays. The unique first dorsal fin is the most distinguishing feature.

Tail fin

Deeply forked caudal fin, powerful and crescent-shaped, indicative of a fast-swimming pelagic predator.

Pectoral fin

Long, pointed pectoral fins.

Distinctive fins

The highly elongated, free-standing first dorsal fin spines are unique among fish species.

Identification Tips

1. 1

   Dorsal Fin

   The most unmistakable feature is the fan-like first dorsal fin with its seven long, free-standing spines. No other fish in its range has this characteristic.

2. 2

   Body Stripes

   Look for 7-8 dark, vertical stripes on the sides of the body, which are more pronounced in live specimens and can fade after death.

3. 3

   Body Shape

   A compressed, somewhat elongated body with a steep, concave profile from the snout to the dorsal fin origin.

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