How to Identify Pacific Spadefish

To identify Pacific Spadefish (Platax boersii), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Juveniles are typically dark brown to black with a prominent orange or reddish margin on the dorsal, anal, and caudal fins, and often a white or silvery band running vertically through the eye and another on the body. As they mature, the coloration fades to a silvery-grey or brownish-silver, often with faint vertical bands. The fins become less elongated and more rounded.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Deep, disc-shaped body, Highly elongated dorsal and anal fins in juveniles, becoming more rounded in adults, Small, terminal mouth, Large, rounded pectoral fins

Dorsal fin

Single dorsal fin, greatly elongated in juveniles, becoming more rounded and less prominent in adults. Contains 5-6 spines and 30-37 soft rays.

Tail fin

Truncate to slightly emarginate caudal fin, becoming more rounded with age.

Pectoral fin

Large and rounded, typically with 17-18 rays.

Distinctive fins

Anal fin mirrors the dorsal fin in shape and elongation, with 3 spines and 23-28 soft rays. Pelvic fins are also elongated in juveniles.

Identification Tips

1. 1

   Juvenile vs. Adult Morphology

   Juveniles have extremely elongated dorsal and anal fins, giving them a 'leaf-like' appearance, often mimicking dead leaves or detritus for camouflage. Adults have much shorter, more rounded fins and a more uniformly silvery-grey body.

2. 2

   Coloration

   Look for the distinct dark body with orange/red fin margins and white vertical bands in juveniles. Adults are more subdued in color.

3. 3

   Body Shape

   The very deep, compressed, and disc-like body is a key characteristic of all Platax species.

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