Would you credit a fish with finishing up in one? (5)
I believe the answer is:
creel
'up in one?' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'would you credit a fish with finishing' is the wordplay.
I cannot really understand how this works, but
'credit' could be 'cr' (abbreviation) and 'cr' is found within the answer.
'fish' could be 'eel' (eel is a type of fish) and 'eel' is found in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for creel that I've seen before include "Basket to hold fish" , "or another" , "Bobbin rack" , "Lobster pot" , "Lobster catcher" .)