Gobiodon atrangulatus The Green Clown Goby requires a 30 gallon or larger aquarium preferably with branching coral. It will rarely become aggressive towards other fish, but will fight with its own kind in smaller tanks. Therefore, it is best if it is kept with other docile species. The diet of the Green Clown Goby should consist of a variety of frozen meaty foods. If housed in a reef tank with live branching corals, it needs to be fed once a day. If housed in a tank without substrate, it will require several feedings per day.