ok i got a frag of monti danae from mike he got it at the meeting this month i belive.anyway i got to looking at it and one of the knobs on it has a hole in it. well there is some kind of bug in that hole that is going in and out of it like 2 times a second i cant tell what it is if anyone can help that would be cool is it bad good or no big deal
Its a coral barnacle. They don't hurt anything and the coral will be just fine. What you are seeing is its tentacles feeding. The rest of the barnacle has bored a hole in the coral and then the coral just grew over it so all you see is the opening for it to feed. I have seen this hundreds of times looks kinda cool if you ask me. Hope this helps.
I agree with sam, it is mostly common on porities type corals where the skeleton is very soft and porus. also sometimes called christmas tree coral where the tube type worms have bored holes in it. Barnacles also do this. Since this type of monti is encrusting, maybe it's on a similar type of skeleton.