Hi, my motoro stingray never haven't fed massivore delite, she just eats nightcrawlers and feeders "livebearers", I have tryed with pranws, mussels, clamps, but nothing. I have a Hystrix stingray, he accepts massivore delite anytime. Unlike, Motoro, I have tryed to put on pellets a big amount of nightcrawlers in a small box (5 inches x 2,5 inches "square") on the bottom, but she discarded the pellets. It's so difficult looking for nightcrawlers, feeders have an potential risk to transmit disease and parasites to my stingrays. Thanks. My motoro stingray has 7,5" discus width. Thanks.