Valenciennea sexguttata is a species belonging to the family Gobiidae, which is classified in the order perciformes and the class Actinopterygii. It inhabits the sandy and sheltered lagoons near the reefs of the Indian and Pacific Oceans, where they dig holes under coral fragments and sand. We will rarely observe this species in waters deeper than 10 meters.
The body of Valenciennea sexguttata reaches 16 cm in length, and is pale white with iridescent blue spots on the chin and operculum, as well as a small black spot at the base of the dorsal fin. It has two distinctive faint orange-brown stripes extending from the pectoral fins to the caudal fin. On its head, its two eyes are located in an upper lateral-dorsal position, which are large and flanked by yellow orbits.
As a general rule, we will observe Valenciennea sexguttata in pairs since it is a monogamous species. In the case of juveniles they form small groups of individuals. The burrows they dig under the sand can be extremely long. In fact, burrows have been documented that have covered distances of up to 20 meters. It is also very common to find pairs of Valenciennea sexguttata living in symbiosis with certain species of shrimp of the genus Alpheus. In this relationship the Valenciennea sexguttata watches over and alerts the shrimp, while the shrimp is in charge of keeping the burrow ducts in good condition, constantly extracting sand to the outside. In case the goby detects any danger, they are usually constantly in contact with these shrimp, both quickly hiding in the burrow.
The diet of Valenciennea sexguttata is carnivorous based and in fact quite peculiar. It spends the day ingesting sandy substrate that it then expels through its gills, thus trapping the microfauna present in the substrate.
Photos: