While I don't pretend to be any sort of authoritative expert at ALL (I'm still doing my initial research before starting up my own first marine tank) everything I've read indicates that that's fairly unusual. Cardinalfish, both pajamas and Benggais, are supposed to be peaceful and docile... the reef equivalent to tetras.
As I'm wanting to get a few of each variety for my own forthcoming reef tank, I'd be very interested to find out if there's any further input on this subject from some of you far more experienced folks.