I totally agree with Inka4040. There are very few large freshwater fish that NEED live fish. I have read articles on some species of large cichlids (like the peacock pass) that will mostly turn down any food that isn't live, but with persistence can be turned onto non-living prepared fish food in some cases. Many people buying feeders from fish stores are getting them for their oscars, which is weird to me b/c oscars are not picky eaters in general and don't need feeders.