Brislings, fishes (6)
I believe the answer is:
sprats
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">brislings</span>' is the first definition.<br/ ><span class="explanation-format__explanation">('sprat' can be a synonym of 'brisling')</span><br/ ><br/ >'<span class="explanation-format__original">fishes</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(sprat is a kind of fish)</span><br/ ><br/ ></span>
(Other definitions for sprats that I've seen before include "Small fish, set to catch whales" , "Small fish like sardines" , "Couple fussy about meat" , "Small fish used to catch larger ones" , "Small fishes used to catch larger ones" .)