This thread is in reference to Cecil’s column, Can the candirú fish swim upstream into your urethra? (19-May-2000).
My wife works part-time for the fish division of our local University museum. As such, we got invited to the annual fish-division get-together, which consisted primarily of equal parts drinking beer and catching fish. However, one of the non-beer-drinking, non-fish-catching parts was a talk given by a visiting scholar (I think? Not sure of this person’s title) who was researching the candirú.
The talk was part in fun (we got treated to candirú poetry), but also contained some real research information. The speaker was collaborating with a South American medical doctor who completed a candirú removal operation in 1998(?)* The fish had entered the (male) patient’s urethra, been stopped by the urethral sphincter (if that’s the right term), and had turned at a right angle and burrowed into the scrotum. The fish had died, and the subsequent relaxation of its spines facilitated removal. A photograph of the removed fish and part of the affected area(!) was presented.
In addition, some original research was presented, demonstrating that the candirú is not attracted by a number of substances, most notably urine. What actually attracts the fish was unknown, but the researcher concluded that a candirú “attack” is most likely accidental, rather than true parisitism.
*As an aside, I swear I recall this event being mentioned in another thread, but I can’t seem to find it. Maybe I read it elsewhere? According to the speaker, the patient claimed that the fish had swum out of the water up his urine stream (which I found hard to believe); this particular detail rings a bell.