How to Identify Yellowfin Leatherjacket

To identify Yellowfin Leatherjacket (Meuschenia trachylepis), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Variable, typically mottled brown, grey, or greenish-yellow, often with irregular darker blotches and spots. The most distinguishing feature is the bright yellow coloration on the caudal fin, and often on the soft dorsal and anal fins. Some individuals may exhibit blue lines or spots on the head and body.

Scale type

none

Mouth position

terminal

Distinctive features

Rough, sandpaper-like skin due to numerous small, backward-pointing spines (trachylepis means 'rough scale'), Prominent, erectile first dorsal spine that can be locked into an upright position by a smaller second spine, Small, protrusible mouth with incisor-like teeth, Bright yellow caudal fin, Relatively deep body compared to some other leatherjacket species

Dorsal fin

Two dorsal fins; the first consists of a strong, erectile spine followed by a much smaller spine, which locks the first in place. The second dorsal fin is soft-rayed, typically with 33-37 rays, and often yellow.

Tail fin

Rounded to slightly truncate caudal fin, prominently yellow.

Pectoral fin

Small, rounded pectoral fins, typically with 12-14 rays.

Distinctive fins

Anal fin similar in shape and coloration to the soft dorsal fin, with 31-35 rays. Pelvic fin reduced to a single spine, often with a small flap of skin.

Identification Tips

1. 1

   Caudal Fin Coloration

   The most reliable identifier is the bright yellow caudal (tail) fin, which is usually very distinct.

2. 2

   Skin Texture

   Feel the skin; it is notably rough and sandpaper-like due to the small, embedded spines, a characteristic that gives it its scientific name 'trachylepis'.

3. 3

   Body Shape and Depth

   Observe the body shape; it is relatively deep and compressed laterally, distinguishing it from more elongated leatherjacket species.

4. 4

   Dorsal Spine

   Note the prominent, erectile first dorsal spine, which can be locked upright. This is a common feature of filefish but its robustness can be a clue.

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