Sixspot Goby

The sixspot goby is recognized by its pale gray-white body and the bright light blue spots on its cheek and gill cover; there is a small black spot at the tip of the dorsal fin. It is one of the sand-sifting Valenciennea gobies: it fills its mouth with sand, filters it through its gills, eats the small organisms inside and keeps the sand clean.

This useful behavior is also its weak point. In a newly set-up or small aquarium the organisms in the sand are soon exhausted, and without regular feeding the fish wastes away within weeks. The individuals sold are wild-caught. It is more plainly colored than the golden head and orange-spotted sleeper gobies, which have their own pages on the site, but its care is similar.

It lives in the Indo-Pacific from the Red Sea to Samoa, in silty or sandy parts of lagoons and bays at depths of 3–25 meters. It usually lives in pairs in a burrow dug under a rock; in atoll lagoons it forms communities spread over wide areas. It is a monogamous species; pairs stay together for a long time.

• Volume: at least 200 liters; a large sand surface matters more than volume.
• Water: salinity 1.023–1.026 specific gravity, pH 8.1–8.4, temperature 24–27°C.
• Substrate: fine, round-grained sand at least 5–8 cm deep. Coarse, sharp-grained sand strains its gills.
• Rocks: set rocks directly on the glass; it digs under them. It may blow the sand it digs onto rocks and low-placed corals.
• Lid: it jumps when frightened; a lid is essential.
• Reef compatibility: reef safe; it does not touch corals and does not harm shrimp. It consumes small worms and sand stars in the sand.

Carnivorous. In addition to the organisms in the sand, offer sinking food at least twice a day: frozen mysis, brine shrimp, copepods and sinking granules. Make sure the food reaches the bottom. A mature sand bed and a refugium (a separate compartment that produces live food) help a great deal in the long run.

Peaceful and calm; it spends its day sifting sand. It is territorial toward unfamiliar members of its own species and other sand-sifting gobies. When in danger it flees to its burrow.

Good companions: clownfish, cardinalfish, tangs, dwarf angelfish, wrasses, shrimp gobies (if there is enough space).

Avoid: other Valenciennea species (unless a pair), hawkfish and large predators; in a small aquarium, other sand sifters sharing the sand compete for food.

Kept singly or as a mated pair. In the wild, pairs are permanent; finding a mated pair is the best option for the aquarium. Two unfamiliar individuals can only get used to each other in a large aquarium.

The pair lays its eggs inside the burrow; the eggs are guarded in the burrow until they hatch. Spawning can be seen in the aquarium, but raising the planktonic larvae is rarely achieved in a home aquarium.

• Starvation: the most common problem in this species is wasting away once the sand bed is depleted; if the belly becomes sunken, increase feeding.
• Marine ich and velvet: quarantine new fish.
• Jumping out of the aquarium is common.

There is no reliable external difference. During spawning the female's belly becomes fuller; two mated individuals share the burrow.