Last summer I went out in the boat on the pond at night with one of the under water fish viewing cameras. I let the boat drift across the pond as there was an ever so gentle breeze.
The camera has infra red lighting for night use. I would run across the occasional fish, but one thing I noticed on the screen quite often was some type of what I assumed was a tiny bug. It was above microscopic, because it showed up as movement on the screen. Yet it was so tiny it must not have been more than a few pixels on the screen. It moved with jerky movement across the screen. These seemed to be thick in the upper few feet of water in the heat of the summer at night. Water temperature likely in mid 80's.
I was amazed at the life in the water. It was more like a soup than just water. I've also noticed this in the ocean diving. What appears to be very clear water in the day time, during a night dive with lights on, the water resembles more a thin soup of life rather than just water.
Would these tiny critters flitting across the screen likely have been Daphnia? What other small critters could it have been?
Daphnia 
