How to Identify Common bully

To identify Common bully (Gobiomorphus cotidianus), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Highly variable, typically mottled brown, olive-green, or grey, often with darker blotches or bands. Coloration can change rapidly to match the substrate. Underside is usually paler.

Scale type

ctenoid

Mouth position

superior

Distinctive features

Two distinct dorsal fins (the first spiny, the second soft-rayed)., Large, upward-pointing mouth., Robust, somewhat flattened head., Pectoral fins are large and fan-like., Pelvic fins are separate (not fused into a disc like true gobies)., Lateral line is absent or inconspicuous.

Dorsal fin

Two dorsal fins; D1: VI-VIII spines, D2: 1 spine, 9-12 soft rays

Tail fin

Rounded to slightly emarginate caudal fin

Pectoral fin

Large, fan-like, 15-18 rays

Distinctive fins

Pelvic fins separate, I spine, 5 soft rays

Identification Tips

1. 1

   Two separate dorsal fins

   Distinguishes it from true gobies which have fused pelvic fins and often a single dorsal fin.

2. 2

   Mottled coloration

   Helps it blend into its varied freshwater habitats.

3. 3

   Separate pelvic fins

   A key characteristic differentiating it from true gobies (Gobiidae).

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