It is more typical that it smells like bleach.
I would get checked. The only time I smell like fish, is if I ejaculate, and then don't wash for hours afterward. It's enough of a deterrent, that I don't do it.
You may "smell fishy" after intercourse with a woman. Some women have a stronger odor... or have a yeast infection and not even know it. Try inserting your finger in her and smelling if it's her or you. It's a difficult topic to discuss, but you might be able to get around it by buying those new wipes for hygeine and letting her know that you are using one because you feel you want to smell good for her, and nonchalantly offer her a wipe for you?? If it is you, you have a yeast infection, if it's her, she has a yeast infection... perfectly normal, but needs to be treated. Women should NOT have a strong fish odor, nor should you.