Can the Candiru Fish Really Enter the Urethra?

According to various accounts, the candiru fish is attracted to the smell of human urine and can enter the urethra. Therefore, if a person urinates in the Amazon River, he may be the victim of one of its attacks, which could result in the mutilation of the penis. But is this really true?
Can the Candiru Fish Really Enter the Urethra?

Last update: 17 September, 2021

The candiru fish is one of the most feared species in the Amazon, as there are hundreds of strange stories that can frighten anyone. It’s said that this small animal has the ability to enter the penis, lodge itself in the urethra, and live there as a parasite until it’s surgically removed.

Because of these characteristics, the candiru fish is also known as “vampire fish” or “toothpick fish”. Popular stories tell that this animal is attracted to the smell of human urine and that this is what motivates its attack. It’s generally known to attack only other fish.

The candiru fish feeds on blood. Due to its small size, it’s difficult to detect, especially in turbulent waters. It’s said that it takes every opportunity to get into the opening of the penis and cling there with its sharp barbs. But is there really any truth behind all these claims?

What is the candiru fish?

A man standing in the bathroom holding his groin.
The candiru fish is known as the “vampire fish” and legend has it that it’s attracted to urine.

The candiru fish is a small animal that lives exclusively in the Amazon basin (Bolivia, Brazil, Peru, Ecuador, and Colombia). It measures about 1 centimeter and its appearance is similar to that of an eel, although it belongs to the catfish family.

This fish is a parasite. It has a set of spines that are located on the cover of its gills. With them, they attach themselves to the gills of other fish and then feed on the blood of their host.

The candiru fish has no scales. Its body is translucent but becomes color after feeding. It has barbels lined with tiny needle-like teeth. Most of the time, it lives in the riverbed and only emerges to mate or feed.

These fish prefer turbid waters. They penetrate their victim in less than a second. Once they have attached themselves to their prey, they wriggle and bring out a kind of umbrella with which they hook and secure themselves. Then, they immediately begin to nibble at the nearest artery with their sharp needle teeth.

What’s said about the candiru fish?

Stories about candiru fish attacks on humans began to appear in the 19th century. In essence, the story goes that when a person urinates into the water, the fish swims up and with great speed penetrates the penis of its victim. It then climbs up to the urethra, where it clings on. This causes great pain and makes urination difficult.

It’s also said that it can jump into the water and climb up the urine stream. Some claim that the candiru fish also penetrates the vagina or anus with similar effects. At the same time, some believe it can lay eggs inside humans and wreak havoc on the body.

Most frightening of all, according to folk tales, the only way to get rid of the candiru fish is to amputate the penis. This would be the only way to prevent the animal from reaching the bladder, inflaming it, and causing death. There are several accounts of these mutilations.

The only documented case is that of a man named Silvio Barbosa. In 1997, he was treated for a case like this in Manaus (Brazil). According to claims, he endured three days of agony until the doctor Anoar Samad, a urogenital surgeon, extracted the candiru fish from his urethra.

What’s the truth?

A digital illustration of the bladder.

There’s a researcher at the University of Connecticut who devoted several years to the study of the candiru fish. His name is Stephen Spotte, and his findings were condensed in a book entitled Candiru: Life and Legend of the Bloodsucking Catfishes.

When Silvio Barbosa’s case was published, Spotte visited Dr. Anoar Samad to find out what had happened. He presented him with photos, videos, and even the preserved animal. However, none of this convinced the scientist. In his opinion, neither the story nor the specimen was convincing.

Regarding the story, Spotte pointed out that for the candiru fish to penetrate through a stream of urine, it would have to violate the laws of physics. At the same time, the doctor said that he’d removed the fish’s spines to remove it from his patient’s body. However, the specimen was intact and didn’t have the characteristics of a typical candiru.

To verify the candiru fish’s alleged attraction to urine, Spotte conducted an experiment in 2001. The full study was published and the conclusion indicates that there’s no evidence that this is true. The experiment showed that they were not captivated by this substance.

For more mythbusting, read: Myths and Truths about Andropause in Men

The stories appear to be a myth

The data available so far allow us to state that there’s no evidence that the legend of the candiru fish is true. Although there are numerous accounts of alleged attacks by these fish, the truth is that there’s no proof that they’re true.

Therefore, until solid evidence is found, the possibility of the candiru fish lodging in the human urethra is nothing more than a myth. So, there’s no reason to demonize this species or to fear it!

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  • Cochran, P. A. (2005). Candiru: Life and Legend of the Bloodsucking Catfishes.
  • Spotte, S. (2001, 1 abril). Experiments on the Feeding Behavior of the Hematophagous Candiru, Vandellia cf. Plazaii. Environmental Biology of Fishes. https://link.springer.com/article/10.1023/A:1011081027565?error=cookies_not_supported&code=0d614b26-ebd6-49e3-ae37-b2684b392206.
  • Del Basto, J. C. D., Mojica, J. I., & Koyro, H. W. (2018). Morfología externa del pez parásito Paravandellia phaneronema (Miles 1943) (Siluriformes: Trichomycteridae) observada mediante imágenes de microscopía electrónico de barrido. Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales, 42(165), 323-329.