Pop singer risque -- not cold fish (8)
I believe the answer is:
stingray
'fish' is the definition.
(I know that stingray is a type of ray)
'pop singer risque not cold' is the wordplay.
'pop singer' becomes 'Sting' (lead singer of The Police).
'risque' becomes 'racy' (synonyms).
'not' is a deletion indicator.
'cold' becomes 'c' (eg on taps).
'racy' with 'c' removed is 'ray'.
'sting'+'ray'='STINGRAY'
(Other definitions for stingray that I've seen before include "Large fish with tail spine" , "TV show" , "Large venomous fish -- it's angry (anag)" , "Marine creature with venomous tail" , "Poisonous spined fish" .)