Snare ten squirming fish (8)
I believe the answer is:
entangle
'snare' is the definition.
(I've seen this before)
'ten squirming fish' is the wordplay.
'squirming' is an anagram indicator (I've seen this in other clues).
'fish' becomes 'angle' (angle can mean to fish).
'ten' anagrammed gives 'ent'.
'ent'+'angle'='ENTANGLE'
(Other definitions for entangle that I've seen before include "Involve in complications" , "Get tied up in knots in neat glen" , "snarl" , "Entwine into a confusing mass" , "Snare" .)