A slender parasitic catfish indigenous to the Amazon. It attaches itself to the gills of other spiny fishes and extracts blood for food. It occasionally swims into and inserts itself in the urethra or rectum of human bathers, from whom it must be surgically removed. This nearly transparent vertebrate is also known as the “toothpick fish,” ‘Vampire fish,” “carnero,” or “candiru urethra.”