i my experance it can be done but not recomended zoathiads release toxins into the water when there cut,so i try to do it out of the water,i have a plastic dish tub that i fill and use so a fragging stationand i can get like 20 frags started and set for like an hour then i can put them in my sump/frag rack.
if you do frag inside the display i would be prepared to do a water change and change out the carbon to be safe