I have found that some zoa's are very sensitive to flow, some to light. Too high flow, they don't grow, too low and they can actually just 'drop polyps'. Other light/flow situations can cause them to 'brown out' - just close up, get kind of brownish, and fade away slowly. We have some people in this club that seem to have excellent results with zoa's. I'd love to hear from some of them as to whether or not they have to move their zoa colonies around to find a 'sweet spot' - or if they just never have any problems at all. I had 2-3 polyps of 'Darth Maul' that died on me within weeks of getting them. Right next to them a very similar paly (nightmare?) grew from 2 polyps to 15 polyps, and then started dropping polyps. I moved it with about 5 polyps left - now it has 4 polyps, but they are larger than before, healthy looking, and starting to grow again. I hate zoa's...
bob