The most common and most likely answer to this crossword clue is the 7 letter word ROLLMOP
I've seen this crossword clue in The Times
R
O
L
L
M
O
P
More clues leading to the result ROLLMOP
- Cold food after bread is shock
- Food with bread, followed by sponge
- Spoken part doctor originally played? Something fishy here
- Bun might initially work for pickled herring
- With bread, soak up fish
- In submarine, maybe, one who’s elected to conserve oxygen is a cold fish
- Character told to clean fish fillet
- Way for Pom to get some seafood?
- Cleaner’s on list to get food
- Pickled herring to start followed by sponge
Buddy explains!

The straight part
We know that "fish" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fish = rollmop.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ROLLMOP mean?
ROLLMOP noun- A fillet of herring, rolled and flavoured with sliced onion and spices then pickled in brine