I noticed the other morning, upon waking up, that I have what I think is a sea star. I don't have a pic, sorry! But it's about 2 cm across, is off-white, and seems to have that "chubby" look that the sea stars do. I browsed a few websites, and I'm pretty sure this is what it is. I have some zooanthus and mushroom corals in there as well. Am I going to have to remove this sea star? Will it attack the corals?