I recently purchased an acab frag from a local fish store. I’m extremely new to the hobby and basically have no experience. The coral was doing fine but I woke up today and discovered a white funnel shaped substance on the side of the coral. I’ve attached a picture, any help would be appreciated.
Looks like mesenterial filaments coming from the side of the polyp. They can send those out through any portion of their tissue and digest stuff outside the polyp. They sometimes will also come out if the polyp got a little damaged from the skeleton during transport.