xenia problem. please help

[fishguy007]

tank is about a month old. i used all dead rock as the lfs told me this was better and would be live in no time.

xenia have been good for weeks till yesterday.

can i bring these xenia back? or are they probably dead??? i really want to know if the xenia will come back.

it seems to have happened after that shrimp brine shrimp overfeeding. but the ammonia went to 0.25 and then back down. everything else in tank is ok.

nitrite = o
ph = 7.8-7.9
nitrate - 0
ammonia - 0

i posted some pics of what they look like below

please help
what else could be wrong???????