Definition
A heliozoan is a single-celled organism belonging to the group Heliozoa, characterized by its spherical shape and radiating, needle-like pseudopods called axopodia. They are like microscopic suns floating in freshwater. Heliozoans use their axopodia to capture food particles. They are found mainly in freshwater environments, such as ponds and lakes. Some have protective scales or spines. These organisms are an important part of the freshwater food web.