This was posted on Dr. Ron's forum:
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Haven't posted in a while, but check semi-regularly and this thread caught my eye.
Why? Well, here's the thing... yeah, I have Asterina in my tank. No, they don't eat Stonies, not that I've observed. BUT, if I introduce Zoanthids... gone, in a matter of days.
Slowly some of the Stars will approach the polyps. MOST of them don't, but some do. Of the ones that do, most have at least some orange coloration to their upper surface. It seems that all of the individual stars that have this orange speckling will consume the polyps if they can get to them in time. The polyp predator will make it way to an individual polyp, climb up the side to the "top", and place its mouth over that of the polyp, effectively appearing to be just a closed polyp unless you get close. Once the polyp is consumed, which may take hours to days, depending on relative size, it's on to the next one. Prior to acquiring a free frag a few months ago, the tank had been zoanthid-less for almost a year. These Stars do not not bother Palythoa or Protopalythoa. Neither do they molest Soft Corals nor Stony Corals that I have seen. In fact, no cnidarian other than Zoanthids seem to be on the menu. Now, I'm perfectly content to forego zoanthids, but what I really want to know is what I have here. Is this just odd feeding behavior/preference? Or do I have some weird and unknown species? I'd be glad to provide samples to anyone interested as long as they provide the "bait" to be assured of getting one that does consume the polyps.
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The sum of my knowledge is great, the sum of my ignorance greater still
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