I'm new to all gardening related topics so I can appreciate some help. I started to inspect more carefully my plants and I found what the picture show. All the leaves have black dots that look randomly distributed. I suspect it can be some form of fungi or plague but I have no experience.
The picture is not close enough to give me a clear picture of the problem, but my guess is you are correct with 'fungi'(fungus is singular for one disease) and way off when it comes to the plague. Just pinch those leaves off. They grow quickly and will replace with new leaves in no time. If what is often called black spot starts to really spread then you can apply a fungicide that says it treats black spot. Otherwise don't bother. Never spray the flower, just the tops and bottoms of the leaves.