Tapeworms do not typically cause clinical signs in dogs or cats.  The most common tapeworm that our companions are infected with is caused from eating an adult flea.  Pets most likely ingest the flea from self-grooming.  Tapeworms are long, flat segmented worms that attach to the intestinal wall of the host animal.  Each segment is called a proglottid and usually that is what owner’s notice when it is passed through the stool.  The segments that you may see are described a “white rice-like worms that sometimes move” even though they are only one segment of the much larger adult.  Again, these intestinal worms do not generally cause a pet to become ill, but they are unsightly to say the least!  Usually these worms are diagnosed from visual description or exam.  Typically, they cannot be seen on a fecal float.  A pill is given to treat for this parasite but a topical treatment may be prescribed for some cats.