(WPF)

It looks like microorganisms have something in common with fishes. There are top dwellers and bottom dwellers. In the case of mudpuddles, the thicker and newer plants float on top of the water and the water at the bottom is nearly clear of vegetation. Organisms at the bottom of the mudpuddle appear to be smaller and rounder than those close to the surface. There is less motion at the bottom of the water too.

https://youtu.be/99r1HXD2HGE