That is a Rose Bubble Tip Anenome that has been stressed and expelled part of its zooanthellae. This is commonly called "bleaching" because it is like throwing a red sock in bleach depending on how much you bleach it; the sock may turn lighter pink or it may even turn white. If you kept subjecting the sock to pure bleach it would eventually disentigrate as a stressed coral that bleaches can eventually die if you keep stressing it. The zooanthellae allows corals to use light to make food. With proper tank conditions, good flow, a decent amount of light, and most importantly regular feedings your anenome will survive and regain its color (a deep shade of red). Feed your anenome mysis shrimp, uncooked salad shrimp, or other meaty seafoods. Anenomes are not a begginer coral so if you are not prepared to meet the needs of this demanding and now malnourished animal I would return it. Hope that helps.
-Tom-
