Go into chippy, if fish goes first (5)
I believe the answer is:
enter
'go into' is the definition.
(enter can mean to go into a place)
I don't understand how the rest of the clue works.
(Other definitions for enter that I've seen before include "Make a record of" , "A key on the right" , "Go in - set down" , "Come in - penetrate - record" , "Register (as a competitor)" .)