Hi. At 7 weeks, he shouldn't have been taken from his mother. It's really a little too young as he would still be weaning. The best puppy foods are listed on the website link below:
I would also be aware of quantities according to age and size of your dog. Too much food at once will almost certainly cause gastric and digestive upset, so only tiny amounts but feed about 4 times a day (with the total coming up to the recommended daily amount for your particular puppy).
Also, and just an obvious precaution, I'm assuming your puppy has had his vaccinations for things like parvovirus?
Tony gave you good advice. The puppy should be gradually weaning to regular food. I akways started my pups on goats milk and baby rice cereal. I then used a good quality puppy food kibble but put in a blender so I could make a gruel out of it. Add a little warm water. You should probably be feeding 4 smaller meals a day. If the pup ears too quickly, get a good size rock, or another smaller cup, etc and put it in the food biwl so the food gets distributed around the sides. This method will slow him down.
I absolutely agree with Tony and Margot.
He is still such a baby! 7 weeks is a little too young to have been taken from his mother and littermates. 8-9 weeks is usually best. Those 1-2 weeks make such a difference.
Never mind. He has you now and you are doing your best.
He probably isn't ready yet for dry food pellets. Margot gives you some good ideas there. Or you can ask your vet?
So long as he doesn't have any other symptoms, like excessive sleepiness, diarrhea, etc. If he does, then he needs to see the vet urgently.
Also be careful because if he throws up, he will get dehydrated very easily at such a young age.
Pedialyte (the unflavoured one) or water with a little honey dissolved in it may help him if he has vomited, and you feel he has lost too much fluid.You may need to check out any repeated vomiting with your vet.