Can you swim in the lake?

NO, but you can walk in the stream😏

There is people using paddle boards and if they fall off there are swimming but there is no free swimming in the lake

There are "No Swimming" signs all over the place now.

No

I have never seen signs stating no swimming. It's generally a lake for fishing and Camping. Although I have on occassion watched children and adults cool off in the water. The individuals would get out of the water immediately. I always thought it was because the water was very, very, cold, and because the lake is full of algae. There is not a roped off or designated area like a Beach dedicated for swimmers. If I were to guess if people can swim at Fenton Lake my answer would be No.

No swimming it's not a lake for that

I believe that swimming is prohibited

Nope. Swimming is not allowed there.