Bloater's not a bad sea food item (7)
I believe the answer is:
lobster
'sea food item' is the definition.
'bloater's not a bad' is the wordplay.
'not' suggests deleting specific letters.
'bad' is an anagram indicator.
'bloaters' with 'a' taken away is 'bloters'.
'bloters' anagrammed gives 'LOBSTER'.
(Other definitions for lobster that I've seen before include "Crustacean with pincer-like claws" , "Tommy no longer" , "potted" , "Bolster up te shellfish" , "Large, strong-jawed crustacean" .)