[alaskayorkie]

My .02:

If they're just playing and warning each other when it gets too rough, that's a good thing. But you're right not to let it get out of hand if there's the possibility of injury.

Can you tell what causes the fighting? Is it toys? Food? Affection? Sometimes if you can control the causes, you can control the fighting.

I think the key is really studying whether they're biting hard and hurting one another. If the bites are hard, you need to work on bite inhibition. Let them nibble you, but as soon as they bite hard -- say ouch! Then stop the play while you "lick your wounds."

Good luck!