Aaron, Huerfan et al
as would any LPS or softie - these (KH/PH) must be maintained to make them happy (among other things), also, what Huerfan said, flow, lighting and crowding - and lastly, stress due to moving them - they sometimes stress out after a move (frm one tank to another) and release -
If you have halides, move them out of direct light, that seemed to work for me on my Blues, reds and green stripers.
Good luck,
House