My two 3-week-old kittens have started fighting! They would prance, claw at, screech, try to choke each other for long periods of time. It looks really violent and I stopped them several times by clapping my hands loudly, but then they just rush onto each other again. I just put one of them in the bathroom and the other in the closet but I'm scared they'll start fighting again. What should I do to stop their fighting??