Hour to feed young bear fish (4)
I believe the answer is:
chub
'fish' is the definition.
(chub is a kind of fish)
'hour to feed young bear' is the wordplay.
'hour' becomes 'h'.
'to feed' is an insertion indicator.
'young bear' becomes 'cub' (I've seen this before).
'h' put into 'cub' is 'CHUB'.
(Other definitions for chub that I've seen before include "Thick-bodied river fish" , "Fat relative of the carp" , "Fat freshwater fish" , "Thick-bodied European fish" , "Plump fish" .)