I have 9 WC stingrays, and they have bin hard to turn to other food, exept for the motoros.. But nightcrawlers never fail, they take it everytime, i have never seen a nightcrawler be in my tanks for more then 1 minute before its eaten..And its full of nutritions, works like hell, and easy to get if you have a decent backyard.. Its also buyable at fishstores were they sell stuff for sports fishing, they sell it as bait there.