Crossword Genius

Book associated with running water and fish (5)

Ross

I believe the answer is:

brill

'fish' is the definition.
(brill is a kind of fish)

'book associated with running water' is the wordplay.
'book' becomes 'b'.
'associated with' is a charade indicator (letters next to each other).
'running water' becomes 'rill'.
'b'+'rill'='BRILL'

'and' is the link.

(Other definitions for brill that I've seen before include "Flatfish; excellent" , "marvellous" , "catch, perhaps" , "Fab -- fish" , "Great" .)

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