Freshwater fish and ray circling river (5)
I believe the answer is:
bream
'freshwater fish' is the definition.
(bream is a kind of freshwater fish)
'ray circling river' is the wordplay.
'ray' becomes 'beam' (synonyms).
'circling' indicates putting letters inside (circling can mean going around or containing).
'river' becomes 'r' (abbreviation for river).
'beam' going around 'r' is 'BREAM'.
'and' acts as a link.
(Other definitions for bream that I've seen before include "Swimmer" , "Fish of the carp family" , "Fish found in amber" , "Fish - British classical guitarist, b. 1933" , "Amber kind of fish" .)