Something smells fishy around here

Yes, I mean that literally.  John came into the kitchen to inform me that Catherine was eating cat food.  You really know someone is improving in their English skills when they are able to tell on their siblings.  Anyway, I asked him if he ate any, since this is something that has happened before.  He denied that he had eaten any, and then I leaned down and smelled his breath.  In a vegan family, if someone's breath smells like tuna, you know something is wrong.