It looks like it's expelling some zooxanthellae. This could be considered as a healthy dump, or perhaps the coral is receiving to much light, in which case this would be a bad thing. How long have you had the coral?
I can't see the pic there well but if it's like a bubble, could be splitting a head. That's what mine used to do. Looked like a little air sac or little bubble.
What lights are you using? What lights was it under in the previous tank? The reason I ask is because it looks very washed out/bleached. This could be a photo issue but if the photo looks similar to what the coral looks like it looks REALLY pale.