He was neutered 3 days ago. When I got him his poop was kinda soft but since the neutering it has gotten completely loose what can i do to make it firm.
Could indeed be nerves and the stress of a new home and new food – if you are feeding new food, not what he’s used to.
Shouldn’t have gotten antibiotics for a simple neuter, so that’s out.
If the diarrhea continues another day, please get your dog to the vet for a fecal, you should have him checked out in any case. A fecal can check for bacteria or intestinal parasites and the vet will give you the right meds for your dog.
Leaving a small dog with diarrhea for more than 3 days is very risky, dehydration is a real problem, he can go into shock.
A fecal is not much, so get him to the vet if the diarrhea continues.
You might give him some plain boiled rice with a little white meat, skinless, boneless chicken chopped fine, or white rice with very lean chop meat added – that will help if the diarrhea is just from stress or change, but it won’t do any good if he has an intestinal infection or parasite, so get him to the vet if this continues.