Fish boat (4)
I believe the answer is:
dory
I believe this clue is a double definition.
'fish' is the first definition.
(dory is a kind of fish)
'boat' is the second definition.
(dory is a kind of boat)
(Other definitions for dory that I've seen before include "Fish for a small boat" , "Golden-yellow fish" , "Sea-wolf" , "Marine fish; rowing boat" , "Fish and flat-bottomed boat" .)