Here are the pics of the OP's puppy. After seeing these..I just don't think it is a swimmer pup.
As "mylittlegirls" has already mentioned...this looks more like a structual problem of the legs themselves. This puppy is still very young. Only time and a good vet will help you get some answers and hopefully some treatment for this little one. Good luck with him!!
By the way...your pups are adorable!
