Eggs in ikura don (3)
I believe the answer is:
roe
'eggs in ikura don' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for roe that I've seen before include "eg Caviare" , "shy animal" , "Mass of fish eggs" , "Fish eggs; small deer" , "A mass of fish-eggs" .)