Fish raise trivial objections (4)
I believe the answer is:
carp
I believe this is a double definition.
'fish' is the first definition.
(I know that carp is a type of fish)
'raise trivial objections' is the second definition.
(I've seen this in another clue)
(Other definitions for carp that I've seen before include "Continuously find fault" , "Fish - complain" , "Criticise - fish" , "Fish often kept in ponds" , "Go on at" .)