Saprolegnia

Saprolegnia is a genus of fungus-like organisms, commonly known as water molds, belonging to the order Saprolegniales. These organisms are typically found in freshwater or brackish environments, as well as in wet soils.12

Most species of Saprolegnia are saprotrophic, meaning they feed on dead or decaying organic matter. However, some species are known to cause diseases in fish, plants, and other aquatic organisms. A notable example is Saprolegnia ferax, which can infect living fish and their eggs, leading to a condition often referred to as white fungus disease.132

Water molds reproduce asexually through motile spores called zoospores, which can be of two types. Sexual reproduction also occurs through the fusion of gametes.1