Payment method for fish (3)
I believe the answer is:
cod
I believe this is a double definition.
'payment method' is the first definition.
(cash on delivery)
'fish' is the second definition.
(type of fish)
'for' is the link.
(Other definitions for cod that I've seen before include "A fish; a hoax (slang)" , "Not a real" , "A fish; a hoax, parody" , "Payment arrangement" , "method of payment" .)