Earlier, I searched this site for information about Old Dillon Reservoir. I don't recall the members handle but he made a comment about not being able to catch anything on worms and such. I responded with my comment I will make below but I don't know what happened to the reply.
In the summer of 2015, a friend and I fished Old Dillon. We caught a handful of fingerling goldens each by stripping small nymphs. We saw boat loads of these little guys swimming near the shore at various locations around the lake. I don't think there were any fish larger than the fingerlings but that may be different, this year.