Looks like tightly closed palys,,,, commonly nown as button polyps! Check your water with your test kits and post readings.
Did the LFS that sold it to you tell you what it was, and how to care for it by any chance?
That would have been awful nice of them.
they look like zoas tome"¦i can't tell if the stalks are grainy or not in any of the pics"¦if the stalks have grains of calcium in them then they are palys otherwise they are zoas..
essentially the same animal, and both will grow in a wide variety of locations in your tank from low to high light and low to high flow..if they don't have enough light they will essentially stretch to get more"¦at that point move them up..