hexamita hexamita hexamita is a genus of parasitic diplomonads. it is related to giardia. h. columbae and h. meleagridis live in the intestines of birds. h. muris and h. pitheci live in the intestines of mammals. h. salmonis and h. truttae live in the intestines of fish. hexamita retortamonas (retortamonadida), on left; hexamita, on center, and giardia, on right (both diplomonadida) scientific classification domain: eukaryota (unranked): excavata phylum: metamonada order: diplomonadida family: hexamitidae genus: hexamitadujardin, 1838 species hexamita columbae hexamita meleagridis hexamita muris hexamita pitheci hexamita salmonis hexamita truttae the genus also includes the species hexamita inflata. it is believed that hexamita parasites are one possible cause for head and lateral line erosion ("hole-in-the-head disease") in aquarium fishes.