Final answer:
The symptoms described suggest a case of vaginitis. Wet mount microscopy can be performed for diagnosis, and metronidazole is often prescribed as the treatment.
Step-by-step explanation:
The symptoms described suggest a case of vaginitis, which is an inflammation of the vagina. The itching, copious thin white/grey discharge, fishy odor, and pain with sex are all common symptoms of vaginitis. To confirm the diagnosis and decide on the appropriate treatment, wet mount microscopy can be performed to examine the vaginal discharge. If the wet mount microscopy confirms the presence of an infection, metronidazole, an antibiotic, is often prescribed as the treatment.