This little predatory zooplankton is native to Europe and Asia.  They can grow up to ¾ of an inch in length and eat native Daphnia, which is a food source for many smaller juvenile fish species.  Young fish have difficulties eating the waterflea because the tale often becomes lodged in their throat making them difficult to swallow.  The first people to often find them in a lake are recreational lake users and anglers.  The waterflea tails often get caught on fishing line, downriggers and other recreational equipment.