I have two large (65+ lbs) dogs, ages 4 and 8-9ish. Both of them have developed terrible breath. It literally smells like a dead fish that has been baking in the sun. I can't, for the life of me, figure it out. I've tried brushing their teeth, changing food, dental sticks, everything. Their teeth look like they are in good shape, so I'm not too sure that's where it's coming from. They don't have plaque build up that I can see, and gums look healthy. Lou, who I adopted more recently, didn't have bad breath until a few months after I brought him home. So it must be something I'm doing! Has anyone else experienced this? Or have any tips? Any help is greatly appreciated.