Stegastes

Stegastes, commonly known as Gregories, is a genus of ray-finned fish in the family Pomacentridae. Members of this genus are marine coastal fishes except for S. otophorus, which also occurs in brackish water. These fish are known by the names of damselfish, gregory and major. They are small tropical fish associated with coral and rocky reefs in the Atlantic, Indian and Pacific Oceans. They are sometimes found in the aquarium trade where they are an easy-to-keep fish, but they do not mix well with other fish of their own or other species because of their territorial habits and aggressiveness.