Land of piranhas (4)
I believe the answer is:
iran
'land' is the definition.
(I know that Iran is a Asian country)
'of piranhas' is the wordplay.
'of' says the answer is hidden in the clue.
'IRAN' is hidden in the letters of 'piranhas'.
(Other definitions for iran that I've seen before include "It used to be Persia" , "foreign land" , "It was known as Persia until 1935" , "Asian country" , "bombless state" .)