Most 'feared' algae species are characterized as which type?

• A. Green Algae
• B. Diatoms
• C. Filamentous
• D. Cyanobacteria

Answer: (C)

Growth form matters: algae that form long thread-like filaments can spread rapidly and create dense, cohesive masses that are very hard to remove or control. This filamentous form can clog filters, pipes, and equipment, and it often requires more aggressive or repeated treatments to keep under control. Because of these practical, management-heavy problems, filamentous algae are the ones typically described as the most feared. Green algae and diatoms tend to be less troublesome in terms of forming persistent, blocking mats, while cyanobacteria are dangerous for toxins, but the immediate control and nuisance challenges most people face come from the filamentous growth that can dominate a water body.