Consider fish in wine (6)
I believe the answer is:
regard
'consider' is the definition.
(I know that consider can be written as regard)
'fish in wine' is the wordplay.
'fish' becomes 'gar' (type of gar).
'in' means one lot of letters goes inside another.
'wine' becomes 'red wine' (red is a type of wine).
'gar' put inside 'red' is 'REGARD'.
(Other definitions for regard that I've seen before include "Gaze at; esteem" , "Deem, view" , "Consider; esteem" , "Look steadily at or consider to be" , "Care" .)