Chippy -- go in after fish (9)
I believe the answer is:
carpenter
'chippy' is the definition.
(I've seen this before)
'go in after fish' is the wordplay.
'go in' becomes 'enter' ('enter' can be a synonym of 'go in').
'after' says to put letters next to each other.
'fish' becomes 'carp' (carp is a kind of fish**).
'enter' put after 'carp' is 'CARPENTER'.
(Other definitions for carpenter that I've seen before include "chips?" , "What Jesus was" , "Craftsman" , "Joseph's occupation" , "Wood worker" .)