It's my first time to have a vaginal discharge with fishy odor and a color of light red. no itching, no redness or inflammation. what could this mean?

Bacterial Vaginosis: The most common symptom of Bacterial Vaginosis is an abnormal homogeneous off-white vaginal discharge (especially after vaginal intercourse) that may be accompanied by an unpleasant (usually fishy) smell. STDs could also be involved. These conditions would require antibiotics, BV would also benefit from probiotics and diet changes. See PCP

BV: Sometimes disturbances to the natural bacteria in your vagina (douching, irregular bleeding, unprotected sex, etc) can allow abnl bacteria like Gardnerella to overgrow and cause a fishy odor. It's not sexually transmitted, but can be treated w/ Metronidazole(Flagyl)/Clindamycin/Boric Acid. See your GYN for a prescription and be examined for other potential causes. Nothing urgent/dangerous though.