what are you feeding him, what were they feeding him and what quantity? he really looks way under weight, his ribs and hips are protruding and his belly is really distended, i wouldn't have purchased the puppy in that condition... i dont mean to kill the excitement of having a new puppy, im just concerned for the little guy. You wouldn't necessarily see the worms in his poop, most of them are visible only on a slide under microscope (float test)...i used to do them all the time at the vet i worked for, what kind of tests did they do on him? Take a look at the other puppy posted in this thread.. that puppy looks very healthy, well weighted