Try to catch fish in the corner (5)
I believe the answer is:
angle
I believe this is a triple definition!
'try to catch' is the first definition.
(I've seen this before)
'fish' is the second definition.
(angle can mean to fish)
'in' is a link.
'the corner' is the third definition.
(eg a corner of a shape)
(Other definitions for angle that I've seen before include "Old English settler" , "may be right" , "Perspective" , "Glean (anag.)" , "Gradient" .)