sps polpys turn black?

[klsi]

Recently i discoverd polpys hole turn into a black dots, where it located near the base of the sps. i have a picture attach below you guys can look at it.

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Tried to search on web, but doesn't have much of information.

thanks in advance.

 

[Acronic]

Its hard to tell, the pic isnt in focus. IMO that is withdrawn polyps but without a better pic, thats just a wild guess

 

[palyam]

watch for Acropora eating flatworms..

 

[celebrityovernight]

those dots make me cringe lol. I'm pretty sure they're just retracted polyps.