Fish eggs turned grey, reportedly (8)
I believe the answer is:
stingray
'fish' is the definition.
(stingray is a kind of fish)
'eggs turned grey reportedly' is the wordplay.
'eggs' becomes 'nits' (nit is a kind of egg).
'turned' is a reversal indicator.
'reportedly' indicates a 'sounds like' (homophone) clue.
'grey' sounds like 'gray'.
'nits' in reverse letter order is 'stin'.
'stin'+'gray'='STINGRAY'
(Other definitions for stingray that I've seen before include "Fish with venomous tail" , "Large fish with tail spine" , "TV show" , "menace in the water" , "Poisonous spined fish" .)