The vast majority of these stories are from men. A few naysayers in the comments may bring up the Salmon as a counter to that point, which as we all know is totally capable of swimming up waterfalls…. Well, luckily for everyone reading, this too is very, very unlikely. Our math might be a little off here, but we think that ranks as being quite unlikely.
Is There Really a ‘Penis Fish’ That Swims up the Urethra?
Candiru – The fish that can swim up your penis?
The story is that the fish swims up a stream of urine into a man's penis, then eats it from the inside. But is there any truth to it? Of all the denizens of the Amazon basin, there is none more feared than the tiny fish known as the candiru. Since coming to the attention of science in the early 19th century, this creature has occupied the very darkest recesses of the popular imagination. The reason for this is the candiru's supposed habit of entering the human penis, lodging itself in place with sharp barbs, and feasting on it from the inside — a horror story that is enough to keep your legs firmly crossed for days.
This fish is called the candiru and is a member of the genus Vandellia. The candiru is found in the Amazon region of South America and is a type of catfish. The fish is actually parasitic. It uses spines located on the covers of its gills to attach itself to the gills of other, larger fish. They can be traced back to the 19th and early 20th centuries.
Wikimedia Commons The candiru fish, in an drawing. Of all of the beasts that prowl the Amazon , none is more feared by the locals than the candiru. A river monster feared even above the dreaded piranha; the candiru waits for its unsuspecting prey to step into the river before latching onto it.