I think I've got a coral under attack..

So I just got back in town, and it seems that a bunch of zoos from a new rock I got have somehow gotten to this rock, and now they are crowding around my xenias. In the pictures, you can see parts of the xenias look like they're sort of "melting". In the other, you can see some white slimely lookin stuff on the rocks.
Any ideas?

Looks like runners for the mat of the paly's to me.

I've not known of zoa's paly's, and xenia being aggressive in way towards each other. Not saying it doesn't or couldn't happen though.

The xenias look completely smushed together now, looking like they don't have too much longer.

They look healthy to me, from the pics.

Not anymore, xenias arn't opening and really close together like a blob