HELP - Not sure what happened

[Seagars]

so the first picture is a frag and the second is a full colony. both have or are turning white (dying). i have not changed anything, dosed anything new and everything else in the tank is doing great. Whats the deal?
HELP!!!

 

[Andyf30]

We need more info. Water perams, lighting, etc.

 

[trueblackpercula]

Any new fish? What are you water levels like?

 

[smtank]

How close is what appears to me an anemone? Do you have an anemone that has been on the move?

Parameters are always important when trouble shooting.

Is this a slow process or does it happen rapidly?

 

[Seagars]

All levels are normal. No new fish. Not close to the nem. Just weird that is is these two pieces and everything else is healthy. Some type of coral.

 

[rogerwilco357]

still need all the parameters to figure it out your ph,alk,po4,po3 ,salinity temp etc etc..do you dose what lighting are you using so many factors...just can't say

 

[danil]

First I would check your Alk. Most of STN/RTN cases happen due to Alk swing.
Frag the colony. Frags can survive and you'll have a chance to grow it back.