I have a 6 week old puppy that is not thriving. When he was born, his weight was in the middle of the puppy weights. Several of the other puppies passed him by, but it did not seem to be that bad. When I came home from the Potomac, he was noticeably smaller than the other puppies. Today I thought I'd feed him separately in case the other puppies were hogging the food. He ate normally, then started pacing around. After a minute or so he threw up. He ate most of that and then had a few more mouths full from the bowl. More walking around. A few minutes after that, he had several drinks of water. Never much at one time. More walking around and then he threw up a few pieces of kibble and some water.

This little guy has me really worried. Any ideas?

It could be a million things.... best bet is to take him to the vet and see if he can find out what the problem is, could be worms or as I said a million other things, I don't think anyone here can tell you what it is as they aren't vets that have examined the dog

Have him checked for PRRA. Sounds like it.

Actually, PRAA, "Persistant Right Aortic Arch". Also look in to Canine Megaesophagus.

First, I am so sorry that your baby is having difficulties. Is he vomiting (which involves retching food from the stomach using abdominal muscles) or just regurgitating (bringing undigested food back up after swallowing it). If he is regurgitating undigested food, water or mucus, I worry about persistent aortic arch, which occurs because of a glitch in development. Puppies will not outgrow this disorder but it can be corrected with surgery. In case this is the problem, please contact your vet immediately because your puppy may need help immediately to avoid further damage.

mega-esophagus?

ME He was doing very poorly in spite of all efforts to put on a little weight. Even with proper positioning for 15 minutes after each meal or drink, he failed to gain. I had to let him go. Very sad here today.