Small smoked fish for captain (7)
I believe the answer is:
skipper
'captain' is the definition.
('skipper' can be a synonym of 'captain')
'small smoked fish' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'smoked fish' becomes 'kipper' (I've seen this before).
's'+'kipper'='SKIPPER'
'for' is the link.
(Other definitions for skipper that I've seen before include "Senior pilot" , "one that's put over the side" , "team leader" , "Captain - small butterfly - fish" , "sea-captain" .)