Thanks Doug.
So today upon very close inspection I notice that 6 out of my 7 brain corals are exhibiting this bite mark condition, although the Favia is by far in the worst condition.
I posted a similar thread on the Zeo forums, and a couple people (including lobsterboy from here) have reported similar conditions with their LPS when they first introduced Zeolites due to the nutrients getting lowered too quickly. They have recommended a spurt of heavy Coral Vitalizer dosing, and to hold off dosing Coral Snow until things improve.
It looks like the Filefish might be innocent! I hope so! Even though my boyfriend has named him F'ugly, F'ugly is a pretty cool fish!