Seafood could be good in a blend of tuna and sole (9)
I believe the answer is:
langouste
'seafood' is the definition.
(I know that langouste is a type of shellfish)
'good in a blend of tuna and sole' is the wordplay.
'good' becomes 'g' (abbreviation).
'in' means one lot of letters goes inside another.
'a blend of' is an anagram indicator (I've seen this in other clues).
'and' says to put letters next to each other.
'tuna' put after 'sole' is 'soletuna'.
'soletuna' anagrammed gives 'lanouste'.
'g' placed within 'lanouste' is 'LANGOUSTE'.
'could be' acts as a link.
(Other definitions for langouste that I've seen before include "Seafood is possibly" , "It may be eaten roasted" , "thing to devour!" , "Shellfish" , "something to eat" .)