One sleeping with the fish? (6)

I believe the answer is:

kipper

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'the fish?' is the definition.
(type of fish)

I can't explain the remainder of the clue.

(Other definitions for kipper that I've seen before include "being in bed?" , "One yet to wake" , "One drops off" , "One smoked" , "Cured fish (one having forty winks?)" .)

I've seen this clue in The Sun.

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