The most common and most likely answer to this crossword clue is the 7 letter word BLOATER
I've seen this crossword clue in The Daily Telegraph
B
L
O
A
T
E
R
More clues leading to the result BLOATER
- Fish that is very filling?
- Fish in lake one in vessel catches
- Fish that swells you up?
- I’m leaving Baltimore dressed for such a dish
- Fish consumed in Belvoir regularly
- Left hat outside
- Found in hat, head of large fish
- Someone using vessel to cross lake for fish
- Gondolier eats large processed fish
- Billingsgate titfer held plate for fish
Buddy explains!

The straight part
We know that "fish that’s smoked" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fish that’s smoked = bloater.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 BLOATER mean?
BLOATER noun- A salted, and lightly smoked herring or mackerel.
- A freshwater fish native to the Great Lakes; the species Coregonus hoyi.