Complaining fish?
I believe the answer is:
carp
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">complaining fish?</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for carp that I've seen before include "Continuously find fault" , "Criticise - fish" , "Cavil - fish" , "Fish - grouse" , "Fish - complain" .)