A few days ago I started to notice that one of my zoas had a brown film on it so I cut the infected polyp off and a day later a few more polyps had this film on it so I just threw the colony away. Today I found that another frag of zoas has what appears to be the same fungis so I cut the infected polyp off and threw it away but before that I took a pic of it. I would like to know what it is and what causes it?