For about 3 weeks now, one of the "mouths" of my Hammer Coral has had a huge bubble coming out of it. What is that all about and should I be concerned? I got it from Petco about 5 weeks ago. I know Petco is not a good place to get a coral (or anything living), but it had great color in regular lighting and I couldn't resist. Sorry for the bad pic, I didn't want to turn the 10Ks back on and disturb everything.