Fishy smell from air vents aswell as condensation on the windshield
On the inside when you use the defrost setting? You could have a heater core leak, but that usually smells slightly sweet.
If the condensation feels like normal water (vs slippery like coolant), you may have an AC drain that’s clogged and not draining. When the AC system is running it is always producing water, and that water has to have a way to drain to the outside. It seems counter intuitive, but the AC system runs in the winter as well as the summer. For example if you select the “defrost” setting the AC system runs.