I like Selcon too. There is a good scientific reason to limit the freshwater fish eaten by lions and other SW fish; I can't remember the whole thing, but basically the FW fish are too fatty and cause liver problems over time. But, it is not a problem that will happen suddenly by using guppies to entice a non-eater or the OCCASSIONAL fish treat. Watching lions hunt once in a while is half the joy of owning them.