Fish caught do wriggle (3)
I believe the answer is:
cod
'fish' is the definition.
(type of fish)
'caught do wriggle' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'wriggle' is an anagram indicator (I've seen 'wriggling' mean this (letters wriggle or move about)).
'do' anagrammed gives 'od'.
'c'+'od'='COD'
(Other definitions for cod that I've seen before include "One caught in the deep maybe" , "Play joke on" , "North Atlantic fish" , "swimmer" , "Cash on delivery for hoax" .)