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What is a Candiru?

J. Leach
J. Leach

A candiru, also known as Vandellia cirrhosa or the toothpick fish, is a small, scaleless, parasitic freshwater catfish that is native to the Amazon River region in South America. Candiru belong to the family Trichomycteridae, which includes 207 species of parasitic catfish. For some, the term 'candiru' refers to not just one fish, but to all those within the entire genus of Vandellia. Many sources, however, use the term to refer only to Vandellia cirrhosa.

The eel-like fish can grow up to six in (about 15.24 cm) in length, and has a translucent body with a small head. Not much is known about the breeding habits of this fish. It preys on larger fish by drinking their blood, and, after it has fed, its belly can appear bloated and distended.

Dangerous candirus are native to South America's Amazon River region.
Dangerous candirus are native to South America's Amazon River region.

Its feeding habits have given the candiru an infamous reputation, even more infamous than the piranha. The fish hunts by literally tasting the water. It seeks out its prey by looking for ammonia, a by-product that is expelled from the gills of other fish. When the parasite locates a victim, it forces itself into its victim's gill cavity. Once inside it locks itself in by raising spines on its own gill coverings.

During urination the urethra expands wide enough to allow a parasite to enter.
During urination the urethra expands wide enough to allow a parasite to enter.

When people swim or wade in the waters these fish inhabit, they should be very careful not to urinate while doing so. Human urine contains ammonia, the chemical candiru use to locate prey. During urination, the urethra expands wide enough to allow urine to be expelled, and allow a parasite to enter.

These fish have been known to follow the path of urine into the urethra of unsuspecting people. For instance, there is a well-known case of a man who had to have a six-inch fish surgically removed from his penis, after it had been lodged there for a few days. The fish have to be surgically removed because the spines on its gills make it impossible to remove the fish by pulling it out.

Another fish known simply as a candiru is the candiru asu, and it is often confused with the parasite that feeds on blood. This type feeds primarily on organs and meat. It has a small, circular mouth that is full of sharp teeth, which it uses to chew a hole in its victim. Once a hole is made, the fish eats its way into the body and consumes it from the inside. These fish will not only eat dead bodies, but any body that is incapacitated in the water.

When bodies are retrieved from the Amazon River, coroners often discover bullet-shaped holes in them. Upon closer inspection, an inspector may find that the body is actually full of these parasites. Some corpses have been found to contain hundreds of these fish.

Frequently Asked Questions

What is a Candiru?

A Candiru, also known as Vandellia cirrhosa, is a small, parasitic freshwater catfish native to the Amazon River. It is infamous for its alleged ability to enter the urethra of humans who urinate in the water, although such incidents are extremely rare. The Candiru is typically translucent and can grow up to 17 centimeters in length.

How does the Candiru locate its hosts?

The Candiru locates its hosts by detecting the ammonia or urea that is excreted from the gills of fish. This chemical cue guides the Candiru to its target, where it inserts itself using backward-pointing spines to feed on the host's blood. Its ability to detect similar compounds is what fuels the myths of it targeting human urethras.

Is it true that Candirus can enter a human's urethra?

While there are anecdotal reports of Candirus entering a human's urethra, documented cases are exceedingly rare. According to research, there is only one well-documented case, and even that one is subject to skepticism within the scientific community. The fear of such an occurrence is largely based on local folklore and sensationalist accounts.

What does the Candiru feed on?

The Candiru is a parasitic fish that primarily feeds on the blood of larger fish. It uses its sharp teeth to latch onto the gills of its host, where it can consume blood without being easily dislodged. The fish's feeding habits are crucial for its survival in the nutrient-poor waters of the Amazon.

Can a Candiru be removed once it has entered a host?

If a Candiru does enter a host, removal can be quite difficult due to its barbed spines. In the rare event of human infestation, surgical intervention is often required. Traditional removal methods used by local populations involve herbal treatments, but these are not scientifically validated.

What habitats are Candirus found in?

Candirus are found in the Amazon and Orinoco River basins, thriving in the freshwaters of South America. They prefer turbid, fast-flowing waters where they can easily find host fish. Their presence is often unnoticed due to their small size and translucent bodies, which provide excellent camouflage in their natural habitat.

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    • Dangerous candirus are native to South America's Amazon River region.
      By: alelina
      Dangerous candirus are native to South America's Amazon River region.
    • During urination the urethra expands wide enough to allow a parasite to enter.
      By: rob3000
      During urination the urethra expands wide enough to allow a parasite to enter.