My girlfriend's vagina smells like fish

She most likely has bacterial vaginosis or some other type on infection. A healthy vagina generally does one have fish smell let alone a bad one.

 

Well i hope that she cleans up before you go down on her, i myself never ran across a woman that smelled fishy

 

There is no way to politely tell her. I tried that once and was told "I'm sorry you don't like my odor..." A month later she was at the doctor with vaginitis. And Hoop, get to a doctor before your cock rots off!

 

I'll admit my semen will start to smell fishy if it "sits" for a while; say if I wait until tomorrow to shower but ejaculated tonight and remnants of my cum haven't fully dried overnight. My cum doesn't smell or taste fishy otherwise. So when someone says a vagina smells fishy (like tuna) it makes me wonder to what extent a guy might be to blame.

I've heard that women should take a bath, not just shower, to fully cleanse her vagina after sex to help remove any leftover semen. Bathe, douche, etc... If semen is not the source of the off-odor then maybe it's due to an infection, hormonal changes or a lack of proper hygiene. An ob/gyn should be able to spot the cause and treat it accordingly if it's more than the women's natural scent.

 

Sorry, I meant to type: to what extent "a guy's semen" might be to blame, not "a guy". Although I can also see how a guy might contribute to this problem beyond just his semen. Poor hygiene etc...