While,
ime, they are not aggressive towards other fish, they are very skittish and prone to jumping. Another issue is they are a harem fish, the square spot is the male, the female is a pinkish yellow color with no square (still a pretty fish, but not as stunning as the male), if the male is not kept with a group of females, it will change sex to female. All anthias are considered fish to be kept by experienced aquarists onlyy. I would highly recommend you do a google search for articles on anthias, reading all you can prior to purchasing one.