Crustacean caught with light line by angler, perhaps (8)
I believe the answer is:
crayfish
'crustacean' is the definition.
(I know that crayfish is a type of decapod)
'caught with light line by angler perhaps' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'with' says to put letters next to each other.
'light line' becomes 'ray' (I've seen this in another clue).
'by' means one lot of letters go next to another.
'angler perhaps' becomes 'fish' (angler is a kind of fish).
'c'+'ray'+'fish'='CRAYFISH'
(Other definitions for crayfish that I've seen before include "Freshwater crustacean" , "Edible crustacean" , "Lobster-like crustacean" , "Catch" , "Lobster" .)