Valenciennea helsdingenii (Bleeker, 1858)

Common Name and Body Shape

This species, commonly called the twostripe goby, has an elongated, laterally compressed body.

Size

It commonly reaches 18 cm (7.1 in) in length, with a maximum recorded length of 25 cm (9.8 in).

Base Body Coloration

Its body is mostly white to pale gray, with a darker brownish gray dorsal surface.

Longitudinal Stripe Characteristics

Two prominent longitudinal stripes run along the sides of its body; these stripes may be orange, dark red, reddish-brown, or black, and are darkest at the anterior end, lightening toward the rear of the body.

Upper Stripe Position

The upper stripe starts at the front of the snout, runs through the eye, and ends at the tip of the upper fork of the caudal fin.

Lower Stripe Position

The lower stripe runs parallel to the upper one, starting at the side of the upper lip, passing through the middle of the pectoral fin base, and ending at the tip of the lower fork of the caudal fin.

Stripe Outline at Caudal Fin

Both stripes are outlined in white at the caudal fin.

Dorsal Fin Spot

A large oval black spot sits between the third and fifth spines of the dorsal fin.

Pelvic and Dorsal Fin Connection

The pelvic fins are completely separated, and there is no connecting membrane between the first and second dorsal fins.

First Dorsal Fin Structure

The first dorsal fin is shallow with a rounded margin, and its fourth spine is slightly longer than the other spines.

Caudal Fin Variation by Age

Adult twostripe gobies have a deeply notched caudal fin with two long filaments, while juveniles have more rounded caudal fins.

Distribution Range

Twostripe gobies have a wide distribution across temperate and tropical waters of the Indian Ocean and western Pacific Ocean.

Specific Range Localities

Their range extends along the coast of East Africa, and includes the southern Red Sea, the Maldives, southeast India, Sri Lanka, Southeast Asia, Australia, western Oceania, and Japan.

Population Abundance

This species is relatively rare.

Social Behavior and Substrate Association

It usually occurs in pairs, but may also be found alone on silty flat sand patches or rubble substrates.

Habitat Preference

It typically inhabits outer reefs at the base of coral or rocky dropoffs, and only rarely occurs in lagoons.

Diet and Feeding Behavior

It is a carnivorous species that feeds on small fossorial (burrowing) invertebrates by sifting prey from mouthfuls of sand.

Spawning and Larval Development

After spawning, eggs hatch within two days; larvae reach a length of 5.25 mm (0.207 in) 35 days after hatching.

Juvenile Habitat

Juveniles are most often found near rocks in clear estuaries.