Fish of the Month: Eyebar Goby - Shoulderspot Goby - Gnatholepis anjerensis - Gnatholepis cauerensis

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FISH OF THE MONTH - NOVEMBER 2004

EYEBAR GOBY / SHOULDERSPOT GOBY
Gnatholepis anjerensis / Gnatholepis cauerensis

Eyebar Goby Gnatholepis anjerensis

Shoulderspot Goby Gnatholepis cauerensis

Here are two common gobies which look much alike and occur in similar habitat. Both are pale gray or whitish with markings that help them blend into the sand. Both have a dark line extending through the eye and down the side of the head. Both have a small yellow spot on the "shoulder" above the pectoral fin. And both live singly or in groups on sand and rubble at the bases of coral heads, boulders, or walls, retreating into crevices when alarmed.

EYEBAR GOBY
Gnatholepis anjerensis (Bleeker, 1850)
This goby has scattered dark and white specks on the body and a row of smudgy dark spots along the lower side.There is a tiny, scarcely-visible bright yellow spot above the pectoral fin base. The dark lines through the eye do not meet at the top of the head. It tends to live at depths above 40 ft. When sensing a predator, these gobies bob rhythmically up and down, probably to warn other gobies of danger and also to inform the predator that it is detected. The species name is from Anjer, Indonesia, where the fish was first collected. To about 3 in. Indo-Pacific. Photo: Magic Island boat channel, O`ahu. 25 ft.

SHOULDER-SPOT GOBY
Gnatholepis cauerensis (Bleeker, 1853)
This goby has fine dark lines along the side instead of rows of dark spots, and the eye bars meet at the top of the head. The yellow "shoulder spot" is vertically elongated and slightly larger than that of the Eye-Bar Goby. This species usually occurs at 40 ft. or more, slightly deeper than the Eyebar. The name is from Cauer, the locality in Java where Bleeker obtained his specimens. To about 3 in. Indo-Pacific. Photo: Mäkua, O`ahu. 50 ft.