Small, salty fish (7)
I believe the answer is:
anchovy
'small salty fish' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for anchovy that I've seen before include "Small salty fish" , "Small edible fish" , "Small fish of herring family, nice on toast" , "Small, salty-tasting fish" , "Small fish, may be served with toast." .)