Dudley USED to this when he was younger...there is a cute little puppy face on the bottom of his water dish, maybe he was trying to get it.
THEN after having him in the pool (during this time) we come to realize this.... He loves biting at bubbles, so we noticed when he paws at his water it creates bubbles for him and next thing you know, it's all over
I have his bowls on a place mat w/ a rubber back on our wood floor, works great