Fish that's hard for young bear to catch (4)
I believe the answer is:
chub
'fish' is the definition.
(chub is a kind of fish)
'hard for young bear to catch' is the wordplay.
I cannot really see how this works, but
'hard' could be 'h' (abbreviation used in pencil classifications) and 'h' is found within the answer.
'young' could be 'cub' (cub is a kind of young) and 'cub' is found in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'that's' is the link.
Can you help me to learn more?
(Other definitions for chub that I've seen before include "Small river fish of the carp family" , "European freshwater fish" , "Fat freshwater fish" , "Thick-bodied European fish" , "Plump fish" .)