Criticise the fish (4)
I believe the answer is:
carp
This clue is a double definition.
'criticise' is the first definition.
(I've seen this in another clue)
'fish' is the second definition.
(I know that carp is a type of fish)
'the' is the link.
(Other definitions for carp that I've seen before include "Raise trivial objections" , "Fish - grouse" , "Fish - complaint" , "ish" , "Keep complaining" .)