How to Identify Silver Biddy

To identify Silver Biddy (Gerres oyena), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Overall silvery, often with a darker dorsal surface and lighter ventral side. Juveniles and sometimes adults may exhibit faint vertical bars or spots on their flanks, which can fade with age or stress. Fins are typically translucent or dusky.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Highly protrusible mouth, forming a downward-pointing tube when extended., Deeply forked caudal fin., Large, deciduous scales., A prominent black blotch on the spinous dorsal fin (more pronounced in some individuals/juveniles).

Dorsal fin

Single dorsal fin with 9-10 spines and 10-12 soft rays. The spinous portion is typically higher than the soft-rayed portion.

Tail fin

Deeply forked caudal fin.

Pectoral fin

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

Distinctive fins

Anal fin with 3 spines and 7-8 soft rays. Pelvic fins are thoracic, with 1 spine and 5 soft rays.

Identification Tips

1. 1

   Mouth

   Observe the highly protrusible mouth, which can extend significantly downwards to form a tube for sifting substrate. This is a key characteristic of the Gerreidae family.

2. 2

   Coloration

   Look for the overall silvery body. While faint bars or spots might be present, the dominant color is reflective silver.

3. 3

   Dorsal Fin

   Note the single dorsal fin with a distinct black blotch on the spinous portion, especially in younger individuals. Count the dorsal fin spines (9-10) and soft rays (10-12).

4. 4

   Pectoral Fins

   The long, pointed pectoral fins are also a good identifying feature, often extending past the origin of the anal fin.

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