When a woman has a fishy smell after sex, there are two possibilities: first, when a woman has intercourse, the man does not take any contraceptive measures and ejaculates directly into the woman’s vagina, which can cause a fishy smell after intercourse. This is a physiological manifestation caused mainly by the male semen, which often does not require any treatment and does not affect the woman. The most common type of vaginitis is bacterial vaginitis.