Fishey smell.espeacally after sex.no discharge

I used to have that, the way I stopped mine is by not wearing underwear when I am in pajamas. And if I shower or take a bath at night sometimes I lay in my bes with just a towel for half and hour. Also make sure to never douche. It is really inhealthy and just causes the odor. It needs to self clense and breathe once in a while. I know there are a few other causes but these are the ones I had and the main ones I've heard of.

Fishey smell.espeacally after sex.no discharge

Sounds very much like bacterial vagniosis, or BV. Make an appointment with your doctor for proper diagnosis and treatment.