Dont put that coral next to that one!

Space hadnt been a problem before.  I always could have all the coral have all its own space, not worrying about anything interacting.  Things are starting to get more crowded and pretty soon corals are  going to go from having its own house to living in a townhome.   

Most corals like to be spaced atleast a little bit. One reason can be them stinging each other, another reason is faster growing corals can shade/overgrow other corals.

I'm probably the most recent example, the only problem I've had were my green acans and my green fuzzy mushroom expanded and killed my whole colony of acans

This is at night, when most of the sweeper tentacle activity occurs. This Pearl Bubble Coral was a damaged one that I bought for cheap and was recovering in my tank. It is expanded out about an inch from the skeleton and gets very fuzzy while feeding at night. If there was a coral close enough and upstream from it, it would send out sweepers to protect itself.

Note the LR below it. That is southern Utah Red Sandstone. 

Here is the same coral about 6 months later in a pic taken just before lights out.

They can recover. A new place in the tank would be the best thing to do. Wait it out and see. If by tomorrow it's gone, I mean melted away, one ricordia will not mess up a properly set up reef aquarium.