“Today we are talking about a vampire that glitters in the sunlight, as if you could outswim it… But more on that later.”
In the shadowy depths of the mighty Amazon River, a tiny monster veiled in murky water searches for its next sanguine feast. The Candiru fish is a creature that has both intrigued and instilled dread in those who venture into its domain. Like the cloudy waters it calls home, myths and legends conceal the truth behind this fish’s hunting behaviors. But sometimes cultural whispers shroud nature in an aura of unease in Life, Death, and Taxonomy.
Description
- Looks like a tiny silver minnow
- Thin snake-like body, large eyes, transparent fins
- After eating, its stomach swells like a tick
- Looks like it has a sardine strapped to its belly
Measure Up
Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com. We don’t have a new Measure Up intro!
Length
- 17 cm (7 in)
- How many candiru go into the diameter of Uranus?
- Hint: Uranus is the third largest planet in the solar system. It is a gas giant but since it’s primarily made up of ice, it’s in a new category called ice giants along with neptune.
- 287,500,526 Candiru. Uranus is 51,118 km or 31,763 mi in diameter.
Width
- 3.5 mm (0.13 inches)
- How many candiru widths go into the height of a moriche palm tree?
- Hint: The Moriche Palm, or Miriti, is a tree that grows around the Amazon River. It bears a scaled maroon fruit that is popular as an ingredient in alcoholic beverages.
- 10,294 candiru.The tree can be 35 meters (114.8 feet) tall.
Fast Facts
- Range: Lives in the rivers and basins of the Amazon and Orinoco rivers (1400 mi)
- Diet: Fish blood
- Behavior: Hunting by sight
Major Fact: Swimming Upstream
The candiru is called the vampire fish because it is parasitic. They are hematophagous, which means that they consume blood for sustenance. They find a suitable host fish and swim into its gill chamber. Once the fish finds its way into the gill chamber, its backwards facing spines lock it in place. Then it will bite the fish’s aorta artery and become engorged with blood within a few minutes.
If you are fishing in the Amazon, these nasty guys might drop out of your catches and get fish blood all over your boat.
The candiru is also the subject of a horrifying rumor about attacks on humans. It has been presumed but unconfirmed that the fish is attracted to urea, or other chemicals that are present in fish gills and human urine. Because the fish is attracted to something that is present in human urine, there are stories that say it travels up human urethras.
Cases of candiru attacks on humans date back to 1829. Native people and foreigners working in candiru territory mostly report second hand accounts of the fish swimming up and lodging in male and female orifices (urethras and vaginal canals). However, many of these accounts are speculative, as in a doctor examining patients that speak another language and speculating that they had been attacked by candiru.
A first-hand account was reported in 1891, by a naturalist that removed the fish from a woman himself.
The most famous modern case of a candiru attacking a human comes from Dr. Anoar Samad, who published a 1997 paper (Candiru Dentro Da Uretra) and kept cystoscopic footage of the removal. He also has the fish preserved in a jar. But in 1999, marine biologist Stephen Spotte investigated the claims for his book (Candiru: Life and Legend of the Bloodsucking Catfishes), and found some inconsistencies.
Samad says that he removed it by snipping off the fish spines and pulling it out, the video also shows the fish being pulled out backwards, which would not be possible if the spines were still attached. However, the specimen still has spines.
Many of the claims, including this one, say that the fish jumped out of the water and swam up the urine stream to enter the opening, which is just impossible from a physics perspective. But also, experiments reported in a 2001 paper found that the fish doesn’t react to smell while hunting at all. Rather, they appear to hunt by sight.
Also, on an episode of the Joe Rogan Experience, wildlife biologist, Forrest Galante said that the spines make it so the only way to remove it is to surgically cut open the human host, which I straight up could not find reported anywhere. Reported removals often include flipping the fish around to pull it with the flattened spines or snipping the spines off.
Spotte concluded his investigation by saying the chance that you might encounter such an experience with this fish when you are swimming in the Amazon are “(a)bout the same as being struck by lightning while simultaneously being eaten by a shark.”
Ending: So take a swim down the river, find a nice set of gills to settle down in, and stay away from people’s bits like the candiru here in LDT.