I always put my new ones in the water to see if they can swim. It has been my experience that they can swim for just a bit then they start to sink. They just don't have the energy I guess. I had one (actually it was Misty!) that jumped on a raft that was in the pool all by itself. She missed and ended up in the drink. Thats when I started buying the life jackets! She was a fearless little one! That's how she ended up where she is today I'm afraid.
Molly