Catfish's whisker (6)
I believe the answer is:
barbel
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">catfish's whisker</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 barbel that I've seen before include "swimmer" , "catfish feature" , "fish" .)