Dog's breath smells like putrid fish - Is something wrong?

Hi All,Some background info: I've got a male Cockapoo puppy, ~7 months old. Was just neutered last Friday and had two baby teeth pulled.He's had some issues in the past, including an enlarged anal gland that would not drain (we had it drained, though he didn't want to poop for about 12 hours afterward). Our original vet (who did the draining) told us that our dog may have Anal Sac Disease, but didn't say anything much past that - just that it was an "educated guess" and that he couldn't tell us anything more. Anyway, we looked for a new vet right after that. Fast forward a few weeks, and it seemed like there was a marked shift in the smell of his breath toward a dead fish type of smell.When we first brought it up to the new vet, she said to put some dental additive into his water, which should help. Did that for two weeks and no change. Then, we figured it might be because of the deciduous puppy teeth he had that may have been catching plaque. As stated above, the vet removed those last week. However, the smell is unchanged.Brought it up to the vet again, and she is telling me that she didn't notice anything dental related during surgery, and that it's just normal dog breath. I know plenty of dogs, and there is no putrid fish smell coming from their mouth when they breathe normally. I've looked it up online, and I read that it could be cause by anal gland issues.Has anyone experienced anything similar with their pup? I'm a new parent, so I'm naturally super nervous about everything, and just feel like the vet is brushing off what might be a larger issue. Recommendations on what to do?TL;DR - Puppy's breath went from normal to REALLY bad, with fishy smell. Vet said it's just normal puppy breath. I think it's something else. Advice? via /r/puppies https://ift.tt/2BALqvE