Cod's cousin (4)
I believe the answer is:
hake
'cod's cousin' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for hake that I've seen before include "Common food fish" , "Type of fish" , "Cod-like fish" , "Food fish related to the cod" , "Food fish; rhymes with create" .)