Swimmer died, blot on hospital (4,3)

'swimmer' is the definition.
(sand dab is a kind of fish)

'died blot on hospital' is the wordplay.
'died' becomes 'd' (abbreviation next to the year of someone's death).
'blot' becomes 'dab' (I've seen this in another clue).
'on' says to put letters next to each other.
'hospital' becomes 'san' (short for sanatorium).
'd'+'dab'='ddab'
'ddab' after 'san' is 'SAND DAB'.