Bait fish (6)
I believe the answer is:
minnow
'bait fish' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for minnow that I've seen before include "Small fry" , "A fish; insignificant person" , "he's unimportant" , "Small person" , "Tiny freshwater fish" .)