Fish sought by Marlin and Dory (4)
I believe the answer is:
nemo
'fish sought by marlin and dory' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for nemo that I've seen before include "Captain brought to book" , "Fish sought in film" , "Finding -, animated film" , "commander for the Nautilus" , "- me impune lacessit (motto of Scotland)" .)