Dangerous fish (8)
I believe the answer is:
stingray
'dangerous fish' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for stingray that I've seen before include "TV show" , "Large venomous fish -- it's angry (anag)" , "Dangerous fish" , "Marine creature with venomous tail" , "Large fish with tail spine" .)