Fish bar cut sandwiches (6)
I believe the answer is:
minnow
'fish' is the definition.
(minnow is a kind of fish)
'bar cut sandwiches' is the wordplay.
'bar' becomes 'inn' (I've seen this before).
'cut' becomes 'mow' (as in mowing a lawn).
'sandwiches' is an insertion indicator (to sandwich is to block something in).
'inn' inserted into 'mow' is 'MINNOW'.
(Other definitions for minnow that I've seen before include "A fish; insignificant person" , "Small fry" , "unimportant person" , "Tiddler" , "Small river fish" .)