an order (according to some sources, a class) of golden algae. The Chrysomonadales are microscopic unicellular organisms with one or two flagella. They may be motile or sessile and are often colonial. Some lack a solid case and are able to change shape while others are covered with a test of scales or are enclosed in a case. In addition to autotrophic feeding, many Chrysomonadales are capable of heterotrophic feeding. Some are colorless.
The Chrysomonadales include 70 genera, embracing 500 species. The majority inhabit fresh waters. The mass reproduction of Chrysomonadales results in water weeding, which is often accompanied by an unpleasant odor. Some species serve as indicators of the degree of water contamination.