What vaginal condition is characterized by a "fishy" odor and a greenish discharge?

The condition characterized by a "fishy" odor and a greenish discharge is indeed bacterial vaginosis. This vaginal condition is primarily caused by an imbalance in the normal bacterial flora of the vagina, leading to an overgrowth of certain bacteria, most notably Gardnerella vaginalis. The "fishy" odor is a hallmark symptom, often more noticeable after sexual intercourse or during menstruation.

The discharge associated with bacterial vaginosis is typically thin, grayish-white, and may have a foamy consistency. This distinguishes it from other vaginal infections, which have different characteristics in terms of odor and appearance.

While Trichomonas vaginitis also presents with a greenish discharge and a foul odor, it is often accompanied by additional symptoms such as itching, irritation, and sometimes a more profuse discharge that may be frothy. The other conditions mentioned, such as vulvovaginal candidiasis, typically produce a thick, white discharge without the characteristic odor associated with bacterial vaginosis, and HPV infections do not generally cause unusual discharge or odor-related symptoms.

Thus, bacterial vaginosis is the most fitting diagnosis given the described symptoms.