The most common and most likely answer to this crossword clue is the 5 letter word TENCH
I've seen this crossword clue in The Daily Telegraph
T
E
N
C
H
More clues leading to the result TENCH
- What might be smelt, but no small fish
- Fish stink when head is removed
- One’s labelled ‘coarse’, right out of gutter
- What’s smelt? First off, a type of fish
- Fish king out of ditch
- Smell headless fish
- Fish head leaving terrible smell
- Unpleasant smell, not first to indicate fish
- Fish one decimated when penultimate is caught
- Fish in ditch after river’s drained
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 = tench.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 TENCH mean?
TENCH noun- A species of freshwater game fish, Tinca tinca.