Something on top of a speaker=okay?

We have a (toy) stuffed dog laying on top of one of our floorstanding speakers. Does this affect the sound?  

Do I need to find an identical breed of stuffed dog to put on the other speaker to maintain balance? Does it matter if it's a dog, an elephant or a cute bunny? What about the color? We can dye the dog's fur if that improves the soundstage.