Bass On Small Nymphs?

While night fishing this past weekend, I thought it would be fun to cast for some blue gill on light tackle so I tied on a size 14 bead head nymph I had tied up for pennsylvania trout on 5x tippet and started casting. A few decent sized panfish and perch came to hand, but then rock bass started hitting it. Now it was dark outside and this nymph had one strip of flashabou down the back but other than that it was a dark natural brown. The rock bass were slightly bigger than the panfish, but when 10 and 11 inch rock bass started hitting my nymph it was surprising. Then it happened. The line went tight and I set the hook. One splash and I knew this wasn't a panfish. There was a good bend in the rod and this was a heavy fish. It was dark so seeing the fish was difficult, but as it got closer I got a good look and it was a bass. I laid down on the dock, reached down and pulled a 15" smallmouth out of the water by the mouth. I was extremely surprised that a fish like this would take a small nymph, but the next day a large mouth came out from under the dock and hit the same sized nymph, while small bluegill chased streamers. Here are the pictures.

Sorry the picture is so dark but there was almost no light outside.