Captain succeeded with fish (7)
I believe the answer is:
skipper
'captain' is the definition.
(synonyms)
'succeeded with fish' is the wordplay.
'succeeded' becomes 's' (genealogical abbreviation).
'with' means one lot of letters go next to another.
'fish' becomes 'kipper' (type of fish).
's'+'kipper'='SKIPPER'
(Other definitions for skipper that I've seen before include "Senior pilot" , "One who misses" , "Trawler boss" , "Captain of team or boat - type of butterfly" , "Captain - small butterfly - fish" .)