First part: Video of microscopic examination of a skin scraping from a guppy (Poecilia reticulata) infested with Tetrahymena. Unstained wet mount; magnification, 40× and 100×. Second part: Tetrahymena are seen invading the blood vessels of a primary gill filament. Unstained wet mount; magnification, 100× and 400×.
Courtesy of Dr. Denise Petty.