This is one of those things that is going to drive me out if it's the case... but I notice a few of my acropora colonies have some white marks near their base, I've looked on the smaller frags that I can still remove with a magnifying glass and I don't see any evidence of AEFW, no bite marks (the white skeleton has quite a regular shape to it), no eggs, nothing I can really think of, I've not quite gone so far as dipping it in betadine to see if anything comes off, but I don't know that I would see anything since the betadine will darken everything up. Ok so here are other ideas, since I've noticed this pre-frag swap I'm not attributing it to anything that got past the dipping. -Flow issues, my return pump died, so I went without my Ocean Motion squirting around the tank for a couple weeks, also my Seios seem to sporadically stop working *sigh*... so maybe it's a flow issue that's causing the flesh to die, either too much direct flow (unlikely) or too little. -Asterina star fish, I've seen them on the white parts of the skeleton, however I'm unsure if they're there eating stuff that is now trying to grow on it (algae, etc) or if they are the actual cause. -Other critters, I still got a few "emerald" crabs lurking around in my tank, and I know people have mentioned seeing them attack corals. -Chemical/heat issues, there have been days I haven't dosed the 2-part, I noticed my calcium was reading upwards of 580 somehow before I managed to bring it back down to 440. Those sorts of things. The last one is probably the least probable simple because I don't think only a part of the coral would die. The flow issue I'm also hesitant just because the places where I see the problems really do have different flow patterns, it might be something at night nibbling at it, and the fact it's occuring on the acropora only species on one side of the tank really worries me.