they were gong through a bag of 200 every 2 weeks, with a few real fat ones usually left. but now the last month or so, they seem to have either developed a taste for them, or sharpened their hunting skills
they are not too good nutritionally wise... if you put them in a seperate tank and fed them pellets for a few days then they would be good feeders.... but its really easy to get rays to eat what you want so i dont get why bother with live feeders when they are alot more money....
every once in awhile I buy a dozen or so just to let my rays "hunt" and use there predatory instincts, besides it is fun to watch. But I wouldn't feed this as a rays only staple to their diet. However sometimes if you have a ray that you can't get to eat these are something to try because they do like to hunt living moving food.
I give them to my rays once and a while just for something to play with. they go crazy hunting for the things. to expensive to be a staple in their diet.