How to Identify Spadefish

To identify Spadefish (Tripterodon orbis), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Adults typically exhibit a silvery-grey to brownish body, often with several indistinct, broad, dark vertical bands that may fade with age or stress. The fins are generally dusky. Juveniles are often darker, sometimes almost black, with more pronounced banding and may mimic floating debris for camouflage.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Deep, highly compressed, and almost circular body shape., Small mouth with brush-like teeth., Long, pointed dorsal and anal fins in adults, giving a somewhat triangular profile., Absence of a caudal peduncle notch.

Dorsal fin

Single dorsal fin, deeply notched, with 5-6 spines and 26-28 soft rays. The soft-rayed portion is tall and rounded.

Tail fin

Caudal fin is emarginate to slightly forked.

Pectoral fin

Pectoral fins are relatively small and rounded.

Distinctive fins

Pelvic fins are small and located ventrally. The soft dorsal and anal fins are notably elongated and pointed in mature individuals.

Identification Tips

1. 1

   Body Shape

   Look for the very deep, almost perfectly circular, and highly compressed body. This is the most defining characteristic.

2. 2

   Coloration and Bands

   Observe the silvery-grey to brownish body with faint, broad vertical bands. Juveniles will have more prominent, darker bands.

3. 3

   Fin Shape

   Note the tall, rounded soft dorsal and anal fins, which become more elongated and pointed in larger specimens.

4. 4

   Mouth

   The small, terminal mouth with brush-like teeth is characteristic of spadefish.

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