The most common and most likely answer to this crossword clue is the 6 letter word MUSSEL
I've seen this crossword clue in The Daily Telegraph
M
U
S
S
E
L
More clues leading to the result MUSSEL
- Seafood and beef, you say?
- Might put into speech
- Removing meat from menu, serves exceptional seafood
- Having cut off tails, has to dispose of shellfish
- Item of seafood picked up with not so much hesitation
- Seafood or beef, you might say
- Replacing centrepiece of meal, possibly uses shellfish
- Overheard order for brawn or shellfish
- Confuse the Spanish for shellfish
- Shellfish with a reduction of cucumber hearts sent back
Buddy explains!

The straight part
We know that "shellfish" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case shellfish = mussel.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 MUSSEL mean?
MUSSEL noun- Any of several groups of bivalve shellfish with elongated, asymmetrical shells