Fish skin in batter is fish (8)
I believe the answer is:
brisling
'fish' is the definition.
(I know that brisling is a type of sardine)
'skin in batter is fish' is the wordplay.
'skin in batter' becomes 'bris' (I can't explain this - if you can you should believe this answer much more).
'is fish' becomes 'ling'.
'bris'+'ling'='BRISLING'
Can you help me to learn more?
(Other definitions for brisling that I've seen before include "Norwegian fish" , "Swimmer" , "Sprat sold in a can" , "Small fish of the herring family" .)