Lori, I'm sorry to hear that Decker has become more aggressive. Like Kim said, you need to make sure he knows that you're top cat and you can't let him know that you're scared of him.

My Starr used to be very aggressive with his food when he was younger. He'd swat and growl if any of the others got too close to his food and he'd also try to eat his siblings food. I just watched him and kept telling him no and I made sure that he didn't steal any of his siblings food unless I gave it to him. He's become much better now and sometimes he doesn't even finish his own food.

Hopefully Decker will learn that this isn't acceptable behavior and will grow out of it. I'm also thankful that Starr is a very petite boy. Pearl is larger than him now and I think that Ziggy will also outgrow him soon. This makes him less of a threat to them. Good luck.