It has a filamentous structure that can occur as individual strands or join to form colonies. These colonies have a noticeable parallel arrangement, resembling floating clumps of grass clippings. The cells in Aphanizomenon are generally cylindrical or barrel-shaped and have a pale blue-green color. All Aphanizomenon species are planktonic, capable of creating dense blooms, and have the potential to produce saxitoxins, which are linked to specific toxins.