Fish deft anglers catch easily to begin with (4)
I believe the answer is:
dace
'fish' is the definition.
(dace is a kind of fish)
'deft anglers catch easily to begin with' is the wordplay.
'to begin with' indicates taking the first letters.
The initial letters of 'deft anglers catch easily' is 'DACE'.
(Other definitions for dace that I've seen before include "Chubby swimmer" , "Small river fish" , "Freshwater fish" , "Fish in the carp family" .)