Strange Neon Tetra Behavior At Night

[thisguyek]

Every so often I will witness one or two of my neon tetras going crazy during the night. They float aimlessly through the tank as if dead for a few seconds, then with a quick burst, they will do really tight circles. They do this over and over and over again. I work second shift, so when i get home ill turn on a kitchen light and usually watch the tank for a while. Is the sudden light affecting them?

 

[Parasaurolophus]

Mine do the same at night, first time I saw it I thought they were dieing but I'm guessing when they are floating aimlessly they are sleeping and when they dart they are just startled by the light I don't think its anything to worry about.