The flea thing is concerning, but you mention three vets. Have you actually seen three different vets, or just three in the same practice? I'd be looking for a new vet if I showed one an actual flea and he refused to believe me, show concern, and offer treatment or advice. You are right that you need to treat your home in addition to the puppy to clean up a flea infestation. Sounds like you're working on it.
I can't identify the things in his stool either, but I'd also tend to think it was something he got into and swallowed.
A tapeworm infestation is pretty obvious. One of my dogs had that. You you not only see the rice-grain-like dried up segments around the dog's bottom, if you're looking often, you sometimes see the segments before they dry up when they're still moving. A dog that has had fleas isn't guaranteed to get tapeworm, you know. The flea has to be carrying the tapeworm, and the dog has to swallow the flea.
Take care of the fleas, keep him clean, good nutrition, and you should be able to get him fixed up. Good luck.
I can't identify the things in his stool either, but I'd also tend to think it was something he got into and swallowed.
A tapeworm infestation is pretty obvious. One of my dogs had that. You you not only see the rice-grain-like dried up segments around the dog's bottom, if you're looking often, you sometimes see the segments before they dry up when they're still moving. A dog that has had fleas isn't guaranteed to get tapeworm, you know. The flea has to be carrying the tapeworm, and the dog has to swallow the flea.
Take care of the fleas, keep him clean, good nutrition, and you should be able to get him fixed up. Good luck.