How to Identify Silver Hatchetfish

To identify Silver Hatchetfish (Gasteropelecus sternicla), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Silvery body with a dark, often iridescent, lateral stripe running from the operculum to the caudal peduncle. The dorsal surface is typically darker, ranging from olive-green to brownish.

Scale type

cycloid

Mouth position

superior

Distinctive features

Deep, keeled chest resembling a hatchet blade, formed by greatly enlarged coracoid bones and powerful pectoral muscles., Large, wing-like pectoral fins., Superior mouth, upturned, adapted for surface feeding.

Dorsal fin

Small, located far back on the body, near the caudal fin.

Tail fin

Forked, symmetrical.

Pectoral fin

Greatly enlarged and highly muscular, positioned high on the body, enabling aerial locomotion.

Distinctive fins

Adipose fin absent. Pelvic fins are very small and located ventrally.

Identification Tips

1. 1

   Body Shape

   The most defining characteristic is the extremely deep, compressed body with a prominent ventral keel, giving it a hatchet-like appearance.

2. 2

   Pectoral Fins

   Unusually large and muscular pectoral fins, positioned high on the body, are indicative of its aerial capabilities.

3. 3

   Mouth Position

   An upturned, superior mouth is a clear adaptation for feeding on insects at the water surface.

4. 4

   Coloration

   Silvery body with a distinct dark lateral line, often with iridescent hues.

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