Wanting one more pickled shrimp (7)
I believe the answer is:
'wanting one more pickled shrimp' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe you can see an association between them that I can't see?
This is the entire clue.
Can you help me to learn more?
(Other definitions for tiddler that I've seen before include "Little chap" , "Small fish (colloq,)" , "Minnow" , "Tiny fish, child" , "Small fry" .)