It is normal for semen to have a fishy odor. Men will have a small amount of fishy odor in their semen every time they ejaculate. The composition of semen is mainly prostate fluid, sperm, and a small amount of secretion from the urethral bulb glands and paraurethral glands. The reason is that the prostate fluid secretes arginine, which has a slightly fishy odor, so it is normal for men to have a fishy odor in their ejaculated semen, don’t worry about it. It is also recommended that you should drink more water, if the fishy smell is very heavy, you should have your prostate fluid tested to see if there is a serious inflammation of the prostate fluid, and you should normally have regular semen discharge, not for a long time.