Way fashionable eighteenth century elegist identifies fish (8)
I believe the answer is:
stingray
'fish' is the definition.
(stingray is a kind of fish)
'way fashionable eighteenth century elegist' is the wordplay.
'way' becomes 'st'.
'fashionable' becomes 'in' ('in' can be similar in meaning to 'fashionable').
'eighteenth century elegist' becomes 'gray' (Thomas Gray).
'st'+'in'+'gray'='STINGRAY'
'identifies' is the link.
(Other definitions for stingray that I've seen before include "swimmer" , "Marine creature with venomous tail" , "Poisonous spined fish" , "Fish with venomous tail" , "Dangerous fish" .)