With his mouth shaped basket of thick rods, we see him eat cyanobacteria of the genus Oscillatoria.
In the video Nassulopsis elegans, measuring about 160um (0.16mm) long.
We found it in the freshwater of "Arroyo Grande", Department of Flores, Ruta 3, Km 243, place "Andresito", Uruguay, South America.
Oblique polarized light,
10X and 20X objective
Panasonic GH3 camera
Video link:
https://www.youtube.com/watch?v=J_MnFDFt3Ec
Video preview:

Regards
carlos