Something is eating my coral stone?

[Palindromebaby]

Something is eating my corals! Well just the base but still I don't know if it will kill them eventually or not. I thought I was seeing tunneling in the candy cane (absolutely not sure that is what the smaller branch one is please correct me if I'm wrong) but didn't know if it had always been there. Now there is enough damage I know for certain.

Is this from a fish? All of my fish were supposed sold as reef safe and it doesn't look like fish damage. From a crab? Hermits and emeralds and one little peppermint shrimp live in the tank. One terrible terrible thought I am having is that the lovely LFS didn't tell us about dipping corals when we got started so only our last two batches have had a dip before going in the tank. All purchases of coral have been from clean reputable places even if the first one didn't pass along the benefits of a coral dip.

Any advice would be greatly appreciated. Hopefully this isn't a catastrophic issue.

 

[EmdeReef]

How old is your tank? Parms? Some of the rocks seem a bit new.

What fish do you have?

 

[Luno]

Parameters and age of tank, how long corals have been in there, lights and lighting period, flow lots of info needed