my zoas are sick. I had my first coral and first colony die from this before. The last colony, each polyp would start to shrivle up and spit brown stuff out and then die. Then the tube would get algea all over it and fall off. The last colony I quarantined and iodine dip at least 5-7 times. Still got worse put them in another buddies old tank, sand lights filters heater. and a ton of pods. Anyway don;t know if this is the same thing but is reminding me of it. iodine dipped these guys and then took the pic, using lugols iodine for 20 mins. Heres some pics, one is them a few days ago.