A diner's fresh fish (7)

I believe the answer is:

sardine

'fish' is the definition.
(sardine is a kind of fish)

'a diner's fresh' is the wordplay.
'fresh' indicates anagramming the letters.
'a'+'diners'='adiners'
'adiners' is an anagram of 'SARDINE'.

(Other definitions for sardine that I've seen before include "Young pilchard" , "FRENCH FISH" , "A diner's small fish" , "Swimmer" , "Rinsed a (anag) - fish" .)

I've seen this clue in The Telegraph.

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