Are you sure it is not comin
g from the anal glands
Take a tissue or paper towel and wipe around the anus only, stay away from the vulva
, see if that is the area that has the odor.
You can do the same to the vulva
area and actually put a covered fin
ger just in
side the openin
g. See if that is the area for sure.
Anal gland secretions can have that fishy odor.
If you can't tell, give the back end of her a good washin
g with mild soap, dry and try again