Angel fish circling bottom of wide river (6)
I believe the answer is:
cherub
'angel' is the definition.
(cherub is a kind of angel)
'fish circling bottom of wide river' is the wordplay.
'fish' becomes 'chub' (chub is a kind of fish).
'circling' indicates putting letters inside (circling can mean going around or containing).
'bottom of' suggests the final letters.
The final letters of 'wide river' are 'er'.
'chub' placed around 'er' is 'CHERUB'.
(Other definitions for cherub that I've seen before include "overweight child" , "A heavenly baby" , "Member of heavenly group" , "A chubby infant with wings" , "innocent-looking child" .)