Fish young bear has found hard to eat (4)
I believe the answer is:
chub
'fish' is the definition.
(chub is a kind of fish)
'young bear has found hard to eat' is the wordplay.
I cannot quite understand how this works, but
'hard' could be 'h' (abbreviation used in pencil classifications) and 'h' is found in the answer.
'young' could be 'cub' (cub is a kind of young) and 'cub' is found within the remaining letters.
No letters remain.
This may be the basis of clue (or it may be nonsense).
(Other definitions for chub that I've seen before include "Plump fish" , "River fish; rhymes with public house" , "Fat relative of the carp" , "Fat freshwater fish" , "European freshwater fish" .)