My porcupine puffer accidently inhaled my cowfish on 2 seperate occasions while in a feeding frenzy. Neither time did the cowfish "Exude" anything.
Hes also been picked on by a trigger, having one of his rear horns bitten off and a front horn split into.
If those incidents are not enough to make him release toxins, then I cant imagine what would cause it.
Every tank is different and every fish is different, so what applies to me may not apply to you, but hes got more personality than all my other fish put together and I wouldnt trade him for anything.
I know some of you are sick of looking at my cowfish, but I gotta post the pic again