Sherry you'll love after a portion of fish! (4)
I believe the answer is:
fino
'sherry' is the definition.
(I've seen this before)
'love after a portion of fish' is the wordplay.
'love' becomes 'o' (love means zero in tennis).
'after' means one lot of letters go next to another.
'a portion of fish' becomes 'fin' (fish have fins).
'o' after 'fin' is 'FINO'.
'you'll' acts as a link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for fino that I've seen before include "Type of sherry" , "Bone dry sherry, served chilled" , "Dry Spanish sherry" , "Light dry sherry" , "Driest of the sherries" .)