A different kettle of fish
Meaning
This phrase refers to a completely separate issue, matter, or situation that is distinct from the one previously discussed.
Origin
The phrase conjures a vivid image from a time when fresh fish were boiled directly in a 'kettle'—a large pot, not the modern tea kettle. Initially, 'a pretty kettle of fish' emerged in the late 18th century, ironically denoting a mess or an awkward state of affairs, perhaps from a chaotic fishing expedition or dinner preparation. However, by the early 19th century, people began to use the variant 'a different kettle of fish' to signify something entirely separate or distinct from the current topic at hand, implying a fresh catch, requiring entirely new consideration and preparation, thus evolving into its modern meaning of a completely different matter.
Examples
- I understand your concerns about the budget, but whether we should expand into new markets is a different kettle of fish entirely.
- Training a puppy is one thing, but house-training a cat is a different kettle of fish.