what's causing this?

[T Diddy]

I've had this cyphastrea for a year or more, and it has been growing like crazy. The other day i noticed a bit of die off in one area of new growth near the sand bed.

Any ideas?

with and without flash:

 

[T Diddy]

here's a wider shot with & without flash:

 

[sps_reefer]

do you think it was maybe a pest or something hungry that ate it or maybe it got stung by something, although i didn't see anything close that might have stung it

 

[T Diddy]

thanks for the reply sps reefer. Nothing is within range for stinging. I guess it is possible that something tried to eat it, but I've never noticed it before. The spot seems to be isolated, and is not spreading. I'll post up another pic later.