How to Identify Two-spotted Goby

To identify Two-spotted Goby (Gobiusculus flavescens), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Overall translucent yellowish-brown to greenish-brown, often with iridescent flecks. Males become more brightly colored during breeding, displaying blue and red hues. Two prominent dark spots are present on the flanks: one below the anterior part of the first dorsal fin and another on the caudal peduncle. A dark stripe often runs from the snout through the eye to the operculum.

Scale type

ctenoid

Mouth position

superior

Distinctive features

Two distinct dark spots on the flanks, Pelagic schooling behavior (unusual for gobies), Slender body form, Sexual dimorphism in coloration and presence of breeding tubercles in males

Dorsal fin

Two dorsal fins. The first dorsal fin has 6-7 spines, often with a dark spot on its anterior margin. The second dorsal fin has 1 spine and 9-11 soft rays.

Tail fin

Rounded to slightly emarginate caudal fin.

Pectoral fin

Large, fan-like pectoral fins with 16-18 rays.

Distinctive fins

Pelvic fins are fused to form a disc-like sucker, typical of gobies, but less developed than in benthic species, reflecting its more pelagic lifestyle.

Identification Tips

1. 1

   Body Shape and Size

   Small, slender fish, typically reaching a maximum length of 6 cm (2.4 inches), though usually smaller, around 3-5 cm. Its elongated body is characteristic.

2. 2

   Coloration and Spots

   Look for the translucent yellowish-brown body with two prominent dark spots on the flanks. The first spot is below the anterior dorsal fin, and the second is on the caudal peduncle. Iridescent flecks may be visible.

3. 3

   Fin Structure

   Observe the two separate dorsal fins. The first dorsal fin often has a dark spot on its leading edge. The pelvic fins are fused into a small, weak disc.

4. 4

   Behavior

   Unlike most gobies, which are benthic, Gobiusculus flavescens is often observed swimming in small to large shoals in the water column, particularly above seagrass or algal beds.

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