Perm finally in hairdresser’s place for swimmer (6)
I believe the answer is:
salmon
'swimmer' is the definition.
(salmon is a kind of aquatic vertebrate)
'perm finally in hairdresser's place' is the wordplay.
'finally' says to take the final letters.
'in' is an insertion indicator.
'hairdresser's place' becomes 'salon'.
The final letter of 'perm' is 'm'.
'm' going into 'salon' is 'SALMON'.
'for' is the link.
(Other definitions for salmon that I've seen before include "Pale pink colour" , "Fish; pink colour" , "Sockeye, for example" , "Underwater swimmers" , "Ol' man's keen on the fish (6)" .)