Upright swimmer's shoes are repaired (3,5)
I believe the answer is:
sea horse
'upright swimmer's' is the definition.
(I've seen this before)
'shoes are repaired' is the wordplay.
'repaired' is an anagram indicator.
'shoes'+'are'='shoesare'
'shoesare' is an anagram of 'SEA-HORSE'.
(Other definitions for sea horse that I've seen before include "Small fish with equine-like head." , "Graceful swimmer" , "Upright fish; so here's a (anag.)" , "Marine equine mammal" , "Something fishy here" .)