Embarrassed after fish is burnt (7)
I believe the answer is:
charred
'is burnt' is the definition.
(char can mean to burn or blacken)
'embarrassed after fish' is the wordplay.
'embarrassed' becomes 'red' (someone may blush or go red when embarrassed).
'after' means one lot of letters go next to another.
'fish' becomes 'char' (char is a kind of fish).
'red' put after 'char' is 'CHARRED'.
(Other definitions for charred that I've seen before include "Cleaned" , "Partially burned" , "Blackened by fire" , "Scorched and blackened" , "what's black on surface" .)