Finally catches fish, using sharp object (5)
I believe the answer is:
spike
'object' is the definition.
(spike is a kind of object)
'finally catches fish using sharp' is the wordplay.
I cannot quite see how this works, but
'fish' could be 'pike' (pike is a kind of fish) and 'pike' is found in the answer.
A single letter 's' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for spike that I've seen before include "Frustrate" , "Sharp point; flower cluster" , "Anglo-Catholic comedian" , "Doctor" , "ear" .)