The Candirú fish does, in fact, exist and is attracted to urine. It is found in the Amazon River, mostly at its junction with the Rio Negro. It is a small, parasitic fish and it's usual prey are other river fish. It senses the urea that the fish exudes from its gills and lodges itself in those gills and bores for a blood vessel, attaching itself with its spiney exterior. It has been known to attack humans and can enter the urethra, the anus and, yes, the penis. Although this is rare, it can not survive inside the human body, but can cause infection and extreme discomfort. Because of it's spines, it is difficult to dislodge without surgery, although the locals have a mixture of fruits and berries that will supposedly kill and dissolve the fish. There is a myth that it can travel up a urine stream to enter the penis, but this has been determined to be impossible. | 
