Fish turning bad (3)

I believe the answer is:

dab

'fish' is the definition.
(dab is a type of fish)

'turning bad' is the wordplay.
'turning' says the letters should be written backwards.
'bad' back-to-front is 'DAB'.

(Other definitions for dab that I've seen before include "A small fish - bad one" , "Apply light touches of colour to the fish" , "A fish; light touch" , "Digital radio" , "Gently wipe" .)

I've seen this clue in the Evening Standard.

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