Start fishing for one of a pair (8)

I believe the answer is:

castanet

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'one of a pair' is the definition.
(castanets normally come in pairs)

'start fishing for' is the wordplay.
'start fishing' becomes 'cast' (I've seen this in another clue).
'for' becomes 'anet' (I can't explain this - if you can you should believe this answer much more).
'cast'+'anet'='CASTANET'

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(Other definitions for castanet that I've seen before include "Clicking wood piece" , "instrument" , "Spanish clicker" , "One of a pair in Spanish music" , "musical accompaniment?" .)

I've seen this clue in The Guardian.

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