Immediate cash payment for fish (3)
I believe the answer is:
cod
'fish' is the definition.
(type of fish)
'immediate cash payment' is the wordplay.
I cannot really understand how this works, but
'cash' could be 'c' and 'c' is located in the answer.
The remaining letters 'od' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'for' is the link.
Can you help me to learn more?
(Other definitions for cod that I've seen before include "Initially, pay when you get the goods" , "A fish; a hoax (slang)" , "swimmer" , "Initially, pay when you receive the goods" , "Payment arrangement" .)