I've never worried about this. In fact, my gar will take food out of my hand all the time. Lately I've noticed that he's getting a little more aggressive. He snaps at a dowel rod that I use to move things around and separate fish for feeding (I don't actually hit or poke the fish...just usher them a little so the slow guys can get some food). He's snapped at other things like the cleaning vacuum. Tonight, I think he expected my fingers to have food and he snapped right next to them the same way he does when he takes food from my fingers. So I've been keeping a close eye on him as he has been following my hand around and circling ominously.