I know almost nothing about tissue necropsis..

My hypothesis:

I believe its cause by stress to the coral.. ANY type of stress. I think that any changes to the coral physical or living condition causes tissue necropsis. An example? stray electricity. Ive read a few articles about how stray electricty in the tank could cause RTN/STN. Maybe an old powerhead or another gadget letting out some volts..

In this case..fragging is like cutting someone's arm.. That would cause TONS of stress..

The tricky part about this is.. How come other colonies do fine after been fragged??

Big dilemma..