My guess is if the elegance has the same brown on it that it passed it on to the bubble coral . Did you inspect it and dip it when you got it ? I would remove both and take them out of the tank if you can and put them in a quarantine tank until your sure of what you have . In all my years luckily I’ve never personally experienced bdj Sofia me to know how and if it starts out like this I can’t help you . Do you have a lfs near by that deals in coral for you to show ? Or you may want to repost on this thread with the title what is this or is this bdj? Welcome. I just know they tell you to increase flow , iodine dips and frag off the good remaining parts of the coral . But firs you should confirm that’s what you have . Sorry that’s about all I can tell you