At approximately 7:30pm on Stock Island I saw a triangle shaped craft with 3 lights going from east to west towards Key West. It was silent. I couldn't tell the speed it was going, but my estimate would be between 100-150 mph. It was also flying a lot lower than a normal aircraft. The object looked translucent, although it could have been black because it was dark outside. In a weird way, it also looked like it was rotating. It didn't seem like it was flying flat like a normal aircraft.