a different kettle of fish

be a different kettle of fish

To be entirely different in scope or description from someone or something that was just being discussed. Steve: "So you like your first two roommates, but what about your third one?" Joe: "William? Oh, he's a different kettle of fish altogether." I suppose we could start looking at buying a house now that our baby is on the way, but that's an entirely different kettle of fish!
See also: different, fish, kettle, of

different kettle of fish

Entirely different in scope or description from someone or something that was just being discussed. Steve: "So you like your first two roommates, but what about your third one?" Joe: "William? Oh, he's a different kettle of fish altogether." I suppose we could start looking at buying a house now that our baby is on the way, but that's an entirely different kettle of fish!
See also: different, fish, kettle, of

a different kettle of fish

or

another kettle of fish

BRITISH
COMMON You say that something is a different kettle of fish or another kettle of fish to emphasize that it is completely unlike another thing that you are mentioning. Artistic integrity? Who needs it? Money? Now that's a completely different kettle of fish. Howard was a sweetheart. But Clarisse was another kettle of fish.
See also: different, fish, kettle, of

a different kettle of fish

a completely different matter or type of person from the one previously mentioned. informal
1993 Empire Meryl is the finest actress of her generation but Arnold is, er, a different kettle of fish.
See also: different, fish, kettle, of

a different kettle of ˈfish

(informal) a person or thing that is completely different from somebody/something else previously mentioned: You may be able to read French well, but speaking it fluently is a different kettle of fish entirely.
A kettle in this idiom is a pan in which you can cook a whole fish.
See also: different, fish, kettle, of
References in periodicals archive ?
"Barca are a different kettle of fish. I'm not sure it will affect them, but you saw last season it affected City when we beat them 3-0, it affected Roma.
Fulham can't stop conceding and will suffer a fourth straight defeat 3 Chelsea 1 Tottenham 2 TOTTENHAM were stung by their defeat at Burnley and they can take advantage of the chaos which seems to be engulfing Chelsea by taking all three points at Stamford Bridge 4 Liverpool 3 Watford 1 WATFORD rattled five past Cardiff City and have three successive wins in all competitions, but this is a different kettle of fish. Liverpool to turn on the winning style once again 5 ManCity3 West Ham 0 BUOYED by their Carabao Cup final win and keen to keep the pressure on leaders Liverpool, it's hard to see top-scoring City missing out on the chance to add to their 74 goals so far
I believe nuclear warfare will be a different kettle of fish from the second world war, for example.
A Different Kettle of Fish: A Day in the Life of a Physics Student with Autism
"I would say C02 is a different kettle of fish. It's plant food.
We ve finished most of our development work.Wave energy is a different kettle of fish. The ocean is a very harsh environment.
Some players change clubs at the drop of a hat to boost their bank balance – but Harry Haddock was a different kettle of fish.
Everyone who worked with him at Manchester United can vouch for the fact that he's a top coach - but working as a manager, where the buck stops, is a different kettle of fish. When Meulensteen (left) was drafted in alongside Martin Jol, I did speculate that it might be the forerunner to a change of leadership at Craven Cottage.
PAULO DI CANIO has been sacked - and that makes Liverpool's trip to Sunderland on Sunday a different kettle of fish.
Now if he should offer Guisborough and Nunthorpe instead, well that would be a different kettle of fish, at least we could get on with building the East Middlesbrough Relief Road.
Williams added: "We also have a big offer on Big Buck's in the Long Walk - money back if your horse finishes second to him - and we're 1-3 about Big Buck's" William Hill are also due to offer 5-1 Prospect Wells and spokeswoman Kate Miller said: "There's been plenty of money for his opponents and, while on paper he looks progressive, this is a different kettle of fish." Pricewise, pages 16-17
But Sandbach are a different kettle of fish, and the visitors will have to be fully switched on for this one if they are to give themselves a chance of moving up to first or second spot in the table.
"If it rains it could be a different kettle of fish, but it is not something we can think about at this point".
Brown Panther bolted up with a six-length victory in the King George V Handicap but this is a different kettle of fish.
But heat and humidity are a different kettle of fish because they are things you can prepare for.