The most common and most likely answer to this crossword clue is the 4 letter word CHUB
I've seen this crossword clue in Independent
C
H
U
B
More clues leading to the result CHUB
- Fat that’s shed by fish
- Youngster consuming hot fish
- Fish young bear has found hard to eat
- Youngster devouring hot fish
- Hour to feed young bear fish
- Fish, rather plump, passing by
- See nerve centre of swimmer
- Angelic child is, without hesitation, something to angle for
- Some angle for this striking ascent of Chris Eubank, though losing last three
- Fish must be caught — focus of activity
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 = chub.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 CHUB mean?
CHUB noun- One of various species of freshwater fish of the Cyprinidae or carp family, especially:
- (by extension) Any of various vaguely related marine or freshwater fishes.
- A chubby, plump person.
- Excess body fat.
- An erection (erect penis).
- A plastic or other flexible package of meat, usually ground meat or luncheon meat.