Marine fish (6)
(Other definitions for cod that I've seen before include "Kid" , "Large sea fish- it's a sham" , "A foolish sort of a fish" , "A fool of a fish" , "Payment arrangement" .)
(Other definitions for sea bream that I've seen before include "Fish, valued as food" , "Edible marine fish" , "Fish - seem Arab (anag)" .)
(Other definitions for bass that I've seen before include "deep in the sound" , "Deep-voiced male singer" , "Fish; deep voice" , "Low fellow" , "Fish; male singing voice" .)
(Other definitions for tuna that I've seen before include "Large fish for the strange aunt" , "swimmer" , "Widely-eaten fish" , "A fish; sounds like piano juster" , "Fish sold in cans" .)
(Other definitions for shad that I've seen before include "Fish; dash (anag.)" , "Herring-like fish" , "Fish related to the herring" , "fish that's been caught" .)
'marine fish' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for dory that I've seen before include "another fish wanted" , "Marine fish; rhymes with fable" , "Fish for a small boat" , "Sea-wolf" , "Fish and flat-bottomed boat" .)
(Other definitions for wrasse that I've seen before include "Fish - swears (anag)" , "Bright marine fish" , "Swears about the tropical marine fish with strong teeth" , "Brightly-coloured fish" , "catch in the deep" .)