I've tried to feed my pac frozen mice, but no matter how much I wiggle it he knows that its dead and will not accept it. So I just drop a big live mouse in there and watch him to make sure he bites it good. If he bites it bad (like he did in the video I've linked below) I terminate the mouse myself (somewhat cruel I know, but I like my frog more than mice...).

Kraid broadsides mouse