One Zoa frag died off others fine

Hey guys I have about a dozen types of zoa frags all small $10 frags, and they have all been great spreading onto the rocks and everything, suddenly over a few days, one died off completely.. My parameters are literally perfect, I know people say that but mine are, ammonia 0, nitrites 0, nitrates 0, phosphates 0, calcium 420, alk 9dkh, salinity 1.025, I dont get it, I have no nudis, at all, no zoo pox, and nothing else I could see. except some very small bristle worms on the dying frag, I was assuming they were cleaning up the death... all my zoas we dipped before introducing several times (atleast 3 months have since passed...) the only thing I can think of is my bulldozer of an emerald crab, hes always on them, picking at stuff on them, and occasionally pinches a polyp.. (bast*rd)... Any thoughts on the mysterious die off? I have t5s with actinic, plus leds retrofit white and blue actinic.. I'm confused, I'm afraid there is something even smaller that maybe I can't see that could wipe out all my zoos! HELP! lol

 

Sometimes zoas just melt for no apparent reason if all else is fine don't worry. My tanks full of zoas doing wonderful but I can't keep Kedds Reds alive iffin I tried lol

 

I would't worry to much if it was just that isolated case. I know my GSP will close up completely for up to a week at a time and then come back real strong lol. Same with my zoas sometimes as well.

 

Agree with both above,i've had it happen myself,but one other thought is-do you asterina starfish?Most found in home aquariums are considered reef safe,but there are some species that can munch zoas and other corals,but it's usually rare.

 

nope no star fish, I once saw a brittle star a long time ago but havent since seen him

 

Agreed! I just found out about those starfish myself. I had another member here tell me though that the asterina stars to be worried about for the most part are the ones that you find on the zoas. I have them all over my glass from LR that I introduced from another system.