Rotifers are microscopic animals found in fresh water sources worldwide including  ponds, bird baths, and rain gutters.  There are also a few species that live in saltwater.  When alive, rotifers have a corona with cilia that sweep food into the found. The rotifers shown here were an incidental finding in urine specimen. Most likely, the specimen had been contaminated with fresh water before being submitted to the laboratory. A variety of free-living organisms including nematodes can be found in soil and fresh water. These organisms may be mistaken as parasites when seen in human specimens; therefore, it is important to prevent urine or stool specimens from being contaminated with water or soil when they are being submitted for parasite examination.