This water fleas concept map depicts various types of small active dark or brightly colored aquatic crustaceans. While spiny water fleas pose no threat to humans or domestic animals, their rapid reproduction rates can significantly impact marine life in lakes and ponds. Other than spread prevention, there are currently no known management options for infestations. Water fleas, except for a few predatory forms, feed on microscopic organic matter particles that filter from the water with specialized thoracic limbs, as illustrated in this water fleas concept map. Fish then eat them. Certain water fleas, for example, are the primary food source for nearly all commercial fish in North America's Great Lakes.