i just wait for the day my fish are having a realy excited to eat day.then i try mp if there is compatition in the tank even better they usually hit it when it hits the water(fool them) the only fish i cant break is a 12in st. all other dats and rays broken. rays the same when you see your ray hit food hard try mp feed 1 peice of food at a time for a couple weeks to get this type of feeding agro. i even got them hitting algea waffers