Punt taken on fish shop (6)
I believe the answer is:
betray
'shop' is the definition.
(I know that shop can be written as betray)
'punt taken on fish' is the wordplay.
'punt' becomes 'bet' (punt can mean a bet).
'taken on' says to put letters next to each other.
'fish' becomes 'ray' (ray is a kind of fish).
'bet'+'ray'='BETRAY'
(Other definitions for betray that I've seen before include "Inadvertently reveal" , "Double-cross, sell out" , "Breach the trust of" , "Give away" , "grass" .)