Golden Retriever Breath Issues

[iron man]

So our 6 1/2mo old Golden Retriever has terrible breath. When me and my wife are sitting on the couch, we can smell her breath from across the couch. It smells like dead fish. She hasn't gotten into the trash or drinks from the toilet. Her teeth are white with no noticeable tartar buildup as well as her gums that are a healthy pink. She's on Southern States puppy food from a local co-op here in Virginia. We spray Arm&Hammer Advanced Pet Care Dental Spray on her top and bottom gums every other night but it's not really helping. It really comes when she's panting while sitting still. Am I stuck smelling her stank breath?