Lately, I've noticed small areas on some coral that look dead. These are small areas where there is no polyps...just barren white skeleton. At first, I thought that some sand had landed there and caused that spot to die.
Here's a photo of what I'm looking at.
I suspected that my Majestic angel was nipping the polyps off, but further observation suggests that only investigates the white spots on the coral that are already dead. Even that, he does extremely rarely so he could not be the culprit I originally suspected.

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400 gal reef. Established April, 2007. 3 Sequence Dart, RM12-4 skimmer, 2 x OM4Ways, Yellow Tang, Maroon Clown (pair), Blonde Naso Tang, Vlamingi Tang, Foxface Rabbit, Unicorn Tang, 2 Pakistani Butterflies and a few coral gobies
My Tank:
http://www.canreef.com/vbulletin/showthread.php?t=28436