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. 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.