Odd coral behavior and death question

[Bluetangclan]

OK I have alot of softies in my 65 tank, namely a bunch of zoos, orange recordia, generic greenish brown polyps #231, some pulsing zenia, a large toadstool and although not softies, a few frogspawn heads. I had for awhile in addition to this some yellow polyps, you know the generic yellow ones that grow like crazy that swallow food visibly. Had a whole frag of about 30 individual polyps on a rock, just recently they all died. No sign of anything with any of the others, which to me yellows are one of the tougher of the polyps or at least have been in the past for me. The toadstool i think might be the culprit although I dont know why any toxic agents it produced would have only affected the yellows, especially from the other side of the tank. But when I added the toady thats when the death began. The entire rock is dead now of polyps. I am much more confused than i am upset by this as my ex has plenty more from a colony I gave her a long time ago and the ones she gave me were overgrowing and stinging things in her tank. Whats the deal here, anyone have a clue or is it just a case of selective bio-warfare?

 

[WinkeyWoneye]

I have 2 toadstool leathers, one very small one decent sized, and a small yellow polyp rock with around 10-20 polyps on it. They dont seem to be bothered by the toadstools in my tank. I only have a 39 gal. so they are some what close too. The yellow polyps have actually spread and gotten much larger since I added them.
Like you I also have many ricordia, zoa's. Also have green/brown star polyps, xenia, anthelia, and 2 anemones. Nothing seems to ever bother the yellow polyps though. My mithrax crab even picks the heck out of there stalks, eating the bits of cyano growing on them. They will close while being picked at, but open right back up once the crab has vacated the area. As I'm not much help with the answer I'll be keeping a eye on the thread for a possible answer, as I have many of the same tank inhabitants as you mentioned. I dont have any frogspawn though, wonder if they could be the bio-warfare culprit. Good Luck with it.

EDIT: What kind of lighting are you running? I have a 175w HQI MH/ 2x65w CF actinics combo setup for lighting. (With all my lighting I'm running about 7.3w per gal.) They seem to LOVE the lights as they stretch toward it like crazy once the halide comes on. Also I do target feed the yellow polyps some mysis shrimp once and a while when I'm feeding the anemones.