bubble coral and other corals

[Aquattro]

Patrick, you'll notice on bubbles, hammers, etc, sweeper tentacles extending. These tentacles have higher concentrations of nematocysts (stinging cells) than normal. If they contact another coral, you'll notice tissue death localized at the point of contact. If moved in time, the affected coral can recover.
Keeping 4-5" of space should be more than enough room to avoid agression.