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

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 ?
A Different Kettle of Fish gives a fascinating and helpful insight into the perplexities of everyday existence for people on the autistic spectrum.
David said: "Each mill has its own particular identity but Wern Mill is a different kettle of fish completely.
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.
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.
Despite victory over Hull FC in Super League on Easter Monday, Nathan Brown and his men know it will be a different kettle of fish this time around away from home.
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.
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.
Chelsea are a different kettle of fish compared to Stoke, and people might say that if we lost to Stoke then we haven't got much hope tomorrow," he said.
But heat and humidity are a different kettle of fish because they are things you can prepare for.
It's a different kettle of fish when it comes to the homeless.
But midfielder Lampard - who has never won at Anfield - warned: "It'll be a different kettle of fish for us away from home.
Full browser ?