Parasitic Catfish: Nature's Underwater Opportunists

The Candiru, otherwise known as Vandellia cirrhosa, is a species of parasitic catfish that resides in the vast ecosystem of the Amazon River - an astonishing biological world with its immense variety of aquatic and terrestrial creatures. However, the Candiru distinguishes itself not by its beauty or majesty but rather by its unnerving and unusual behavior: it has been reported to swim up a man's urine stream and invade his body through his urethra. This remarkable belief has been circulating since at least 1829 when German biologist C.F.P von Martius first reported such incidents during his travel throughout South America (Martius, K. F., 1829). While there are disputing views on whether these infiltrations via urine streams are factual or mere local folklore, what remains undisputed is their parasitic nature. Candirus are hematophagous parasites, meaning they feed off the blood of other creatures. Their usual prey prefers large fish, such as catfishes, where they typically enter through gill openings and attach themselves to their host using spiny structures around their mouthparts. Research centered on this fascinating yet horrifying creature suffered from a lack of extensive scientific analysis due to difficulties associated with capturing this almost invisible creature in its natural habitat. It was not until 1997, when ichthyologist Dr. Stephen Spotte traveled to Brazil, that field studies were conducted exploiting indigenous trapping techniques (Spotte, S. et al., 2001). His research found no conclusive evidence that supported urine-attracted behavior in Candiru. However, the frightening reputation of this parasitic fish persists due to the sensational nature of its alleged attacks.