Those are worms. My Discus would get similar feces a few days after feeding blood worms.
I had skin flukes in my Marine tank before and I prazi pro'd the display with no ill affects.
It's worth a shot.
Here is my post on it.
http://www.canreef.com/vbulletin/sho...ight=prazi+pro
Prazi Pro received Kien's blessing so it has to be good then, right??