Fish-egg (3)
I believe the answer is:
roe
This clue is a double definition.
'fish' is the first definition.
(thesaurus)
'egg' is the second definition.
(I know that roe is a type of egg)
(Other definitions for roe that I've seen before include "Hoofed animal(s)" , "Mass of fish eggs" , "Part of fish, sounds like go through water" , "Mass of fish's eggs" , "eg Caviare" .)