Show the harbour has fish (7)
I believe the answer is:
portray
'show' is the definition.
(to portray is to show or depict)
'harbour has fish' is the wordplay.
'harbour' becomes 'port' (I've seen this before).
'has' means one lot of letters go next to another.
'fish' becomes 'ray' (ray is a kind of fish).
'port'+'ray'='PORTRAY'
'the' acts as a link.
(Other definitions for portray that I've seen before include "Paint a picture" , "Delineate" , "Show" , "Use words to describe" , "Describe in words or make a picture" .)