How to Identify Silver Hatchetfish

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

Physical Characteristics

Body shape

compressed

Coloration

Silvery, often with a darker stripe running horizontally along the lateral line. The dorsal surface may be slightly darker, transitioning to a bright silver on the flanks and belly. Fins are generally hyaline (transparent).

Scale type

cycloid

Mouth position

superior

Distinctive features

Deep, hatchet-shaped body, highly compressed laterally, Large, muscular pectoral fins positioned high on the body, Adipose fin present, Superior mouth adapted for surface feeding

Dorsal fin

Small, located far back on the body, typically with 9-11 rays.

Tail fin

Forked, symmetrical, providing propulsion.

Pectoral fin

Extremely large and muscular, extending horizontally, used for 'flying' out of water. Contains 10-12 rays.

Distinctive fins

Pelvic fins are very small and located far back, almost directly below the dorsal fin. Anal fin is long, originating near the middle of the body and extending to the caudal peduncle.

Identification Tips

1. 1

   Body Shape

   Look for the extremely deep, laterally compressed body resembling a hatchet blade. This is the most defining characteristic.

2. 2

   Pectoral Fins

   Observe the unusually large and muscular pectoral fins, positioned high on the body, which are disproportionately large compared to other fins.

3. 3

   Mouth Position

   Note the upturned mouth, indicating its adaptation for feeding on insects at the water surface.

4. 4

   Coloration

   The overall silvery coloration with a potential darker lateral stripe is typical.

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