How to Identify Silver Jenny

To identify Silver Jenny (Eucinostomus argenteus), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Overall silvery, often with a faint dusky blotch on the upper side below the spinous dorsal fin. Fins are typically translucent or dusky. Juveniles may exhibit faint vertical bars.

Scale type

ctenoid

Mouth position

inferior

Distinctive features

Highly protrusible mouth, forming a downward-pointing tube when extended., Deeply notched dorsal fin., Scales extend onto the head and operculum., No scales on the preorbital area (area in front of the eye).

Dorsal fin

Single dorsal fin, deeply notched, with 9-10 spines and 10-12 soft rays. The second dorsal spine is typically the longest.

Tail fin

Moderately forked caudal fin.

Pectoral fin

Long and pointed pectoral fins, reaching beyond the anal fin origin.

Distinctive fins

Anal fin with 3 spines and 7-8 soft rays. Pelvic fins are thoracic.

Identification Tips

1. 1

   Mouth Protrusion

   Observe the mouth, which can extend significantly downwards to form a tube for feeding. This is a key characteristic of mojarras.

2. 2

   Dorsal Fin Spines

   Count the dorsal fin spines (9-10) and note that the second spine is usually the longest, distinguishing it from some other mojarra species.

3. 3

   Preorbital Area

   Check the area in front of the eye (preorbital area); it is typically scaleless in Eucinostomus argenteus, a useful diagnostic feature.

4. 4

   Coloration

   Look for the overall silvery body and the faint dusky blotch below the spinous dorsal fin, which can be more pronounced in some individuals.

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