Risk taken by fish shop (6)
I believe the answer is:
betray
'shop' is the definition.
(I've seen this before)
'risk taken by fish' is the wordplay.
'risk' becomes 'bet'.
'taken by' means one lot of letters go next to another.
'fish' becomes 'ray' (ray is a kind of fish).
'bet'+'ray'='BETRAY'
(Other definitions for betray that I've seen before include "Inform on (someone)" , "Be disloyal to (someone)" , "Sell down the river" , "Reveal (intentionally or unintentionally)" , "Expose" .)