Gobiodon histrio

Common Names: Green clown goby, green coral goby, broad-barred goby, blue-spotted coral goby, acropora goby, gumdrop goby

Type Locality: Bantam, Tongatabou, Amis Islands

Range: Western pacific, westward to the Red Sea and eastward to Samoa

Taxonomic Troubles: Originally described as Gobius histrio. Commonly confused with the similar Gobiodon rivulatus.

Size: 3.5 cm (1.4 inches) TL

Preferred Water Chemistry: Tropical marine, 22 to 28 degrees Celsius (72 to 82 degrees Fahrenheit)

Difficulty: Quite hardy once they start eating well. Imported specimens may be starved, with shrunken bellies; pick your specimens carefully.

Tank Setup: This fish inhabits the interstices of living Acropora coral colonies. In captivity, specimens will accept as their homes other species of corals, as well as nooks and crannies in live rock, but their preferred habitat is between live coral branches.

Feeding: A timid fish that cannot compete for food, best kept with non-aggressive species. Small mouthed, these gobies need very small food items. These fish often require live foods at first, though they usually can be weaned to frozen or prepared foods. Make

Breeding: Although they spawn quire often, wrapping strings of eggs around coral branches, successful aquarium rearing of the tiny fry is rare. This species has been found to be able to reverse sex in both directions, meaning that any two fish can become a breeding pair.

Fish Description

Very large rounded head with laterally compressed body. Light green background with purple stripes on body and several purple bars on the head.

Notes

Like many of their congeners, these stocky little fish are very popular, and for good reason. They are known as coral gobies because they live among the branches of live SPS corals, and they are called clown gobies because of their timid spunkiness and demeanor. Hardy and peaceful, these diminuitve fish are great additions to reef tanks that do not contain any boisterous feeders.

A mature reef with lots of amphipods is perfect. When they spawn, however, they remove the live polyps from the base of the branches around which they wrap their springy spawn. Obviously, the total damage in a large tank with large corals and a pair or two of gobies will be negligible, and the corals will recover, but it could become a concern in some other setups. As clownfish do with anemone, these gobies settle for life in a particualr coral. Outside the protection of their stinging hosts, they are slow, awkward, and tiny--in other words, a snack! This makes it extremely risky for them to travel from one habitat to another in search of a mate.

Clownfish solve this problem by settling as a small group, the dominant individual becoming female, and the first subordinate becoming male, with the others in reserve. THese gobies go one step further; any two fish finding themselves roommates in a coral will become a pair--even if they were the same sex when they met.