This micrograph is of an sample of the pink scum found in the rectangular pond next to Beckman Behavioral Building (see accompanying image). The sample is unstained: the colors seen here are the true natural colors of the microbial cells comprising the material. The pink resolves into aggregates of cells of non-motil, anoxygenic “Purple Sulfur Phototrophic Bacteria”, also known as the *Chromatiaceae*. The green cells are oxygenic phototrophic protozoa. Evidently, the protozoa have red “eye spots”.