Yes, raccoons will attack small yorkie dogs.
It is not safe to ever have them out at night. racoons are nocturnal and scavage for food in the night.
I am sorry about your fish, pond. That sucks.
But, it is a raccoons favorite meal, and they saw those fish as easy , yummy targets.
My parents had a pom. years ago that was attacked by a mother raccoon. The thing nearly chewed off the poms leg. The dog survived with emergency treatment. She was a tiny dog too. Raccoons are agressive and will do anything to eat.
It is not worth the chance one of those , snatching a beautiful Yorkie.