Punch has to look at salmon (7)
I believe the answer is:
sockeye
'salmon' is the definition.
(I know that sockeye is a type of salmon)
'punch has to look at' is the wordplay.
'punch' becomes 'sock' (I've seen this before).
'has' is a charade indicator (letters next to each other).
'to look at' becomes 'eye' (I've seen this in another clue).
'sock'+'eye'='SOCKEYE'
(Other definitions for sockeye that I've seen before include "Breed of salmon" , "Commercially important salmon" , "Type of Pacific salmon" , "Swimmer" , "fish" .)