Coral damage/disease?

[cindre2000]

Over the past three days I have noticed that one of the heads of my Caulastrea echinulata has been showing tissue recession and die off. Its a small frag and due to the sudden 'onslaught' I assume it is not a lighting or flow issue. All of my other originally healthy corals (not ones I am 'saving') are doing fine: Montis, porites, fungia, caulastrea, merulina...; even with fluctuating temp and salinity.

I can check most of my chemicals at my LFS tommorrow; however, I am thinking it may be more likely that this is probably physicial damage caused at some point in time, rather than poor water quality or disease. Could I be right?

Oh, and i just added a pacific pygmy. He has been really shy, and I have not been around the tank enough to see if he has been nipping...

 

[brandonberry]

I thought Caulastrea were impossible to kill. I di have to remove mine from my main display because my blue angel liked the taste of it, but I'm not sure about pygmy angels. None of my pygmy angels have ever bothered Caulastrea, but that isn't to say yours won't. Have you made any changes recently that could have affected this?

 

[cindre2000]

Other than the new angel and topping off the water more frequently there have been no major changes.

The temperature in the tank has been both warmer and cooler than before also.

Here are some pics now that the light is on.