Description

Body design

This is a small goby growing up to 5 cm in length.

The background colour of the body is pale dark grey. From the pectoral fin back to the posterior end of the first dorsal fin the body has a variegated dark pattern that cuts forward from the dorsum to the underside making a reflection of the dark dorsal fin and dividing the body sharply into two contrasting sectors, one dark one pale.

The pale sector that follows has four dark bars, the last being at the base of the caudal fin. Each bar has fine white vertical borders and between these, the body has a pale variegated appearance created by a mixture of scales in different shades.

Head design

The head is mottled dark brown with a line of white spots along the margin of the gill cleft. a paler chin strap and red lines radiating from the eye. The nostrils are tubular.

Fin design

The first dorsal fin is semicircular, sail-like and sharply divided into a paler anterior half with dark patches, and a dark posterior portion with pale patches. The first four dorsal spines extend into rays beyond the fin. The first being the longest and the fourth the least extended. The second dorsal fin is more rectangular, uniformly pale grey with faint brown blotches.

The pectoral fins are transparent with three rows of white segments on the rays. The pelvic fins are partly iridescent blue. The anal fin has distinct vertical bands of brown and blue. The caudal fin is light brown with darker brown patches.

Diagnostic features

The front half of the body is dark, with the remainder pale with brown bars. The first dorsal fin is convex with projecting rays and a reflective blue spot at the apex. Large spots over this fin give it a dark finish that blends with the dark anterior half of the body, further breaking up the profile.

Variation

Some individuals have extraordinarily long rays on the dorsal fin. They may be a different species.

A Red-brown colour phase with seven narrow white bars on the side was observed at Raja Ampat Islands by Gerald Allen. (AE)

Similar species

None