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What the sources say

CandiruVandellia cirrhosa

Every figure, record and mechanism on the Candiru profile was written from a source, and this is the working table behind it: 40 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

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Source
01

Haddad Junior, Zuanon & Sazima 2021

Haddad Junior, Zuanon & Sazima (2021). Medical importance of candiru catfishes in Brazil: A brief essay. Revista da Sociedade Brasileira de Medicina Tropical.

The page saysThe urethra legend says a candiru will swim into the human urethra to feed on blood.
The source saysthey allegedly enter the human urethra or other natural orifices to feed on blood
The page saysThey also say there is no robust evidence that candirus in the group that includes Vandellia react to ammonia or blood in water.
The source saysThere is no robust evidence that vandelliine candirus react to ammonia or blood in water
The page saysHaddad Junior and colleagues call those cases disputed, given the apparent lack of solid evidence.
The source sayssuch cases are disputed due to the apparent lack of solid evidence
The page saysStories say they do, but researchers who examined the published accounts call such cases disputed, given the apparent lack of solid evidence.
The source saysWe examined published accounts ... they allegedly enter the human urethra or other natural orifices to feed on blood ... such cases are disputed due to the apparent lack of solid evidence
The page saysThey also warn that reports on candirus and human health are biased by second- and third-hand accounts, misconceptions and folk tales.
The source saysreports on candirus and their relationship to human health and death are biased by imprecision, second- and third-hand accounts, misconceptions, and folk tales

Source
02

Brejão 2023

Brejão (2023). Vandellia cirrhosa. The IUCN Red List of Threatened Species 2023: e.T49830470A160427716.

The page saysLeast Concern
The source saysIUCN Red List category: Least Concern (LC).

Source
03

Animal Diversity Web, University of Michigan

Vandellia cirrhosa (Candiru). Animal Diversity Web, University of Michigan.

The page saysLet the Host Do the Work
The source saysCandiru are parasites, feeding on the blood of other fish.
The page saysThe candiru (Vandellia cirrhosa) is a parasite: an animal that feeds on another animal in a harmful way without killing it right away.
The source saysan organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death
The page saysIts meal is the blood of other fish.
The source saysCandiru are parasites, feeding on the blood of other fish.
The page saysOnce it finds a host, it heads for the gills. It either forces itself under the gill cover (the operculum) or waits for the cover to open on its own.
The source saysWhen a candiru locates a host (through visual and chemical cues), it heads towards the gills, where it either forces itself under the operculum or waits for it to open naturally.
The page saysThen it latches onto an artery.
The source saysOnce past the operculum, these parasites latch onto the ventral or dorsal aortal arteries.
The page saysThe host's blood pressure pumps blood straight into the candiru's mouth.
The source saysThe host's blood pressure pumps blood straight into the candiru's mouth; these parasites do not "suck" blood
The page saysThe candiru does not suck.
The source saysthese parasites do not "suck" blood
The page saysA meal usually lasts 30 to 145 seconds, and then the candiru sinks and burrows into the river bottom.
The source saysThe length of a single blood meal is usually short, from 30-145 seconds. After feeding, candiru sink and burrow into the river bottom.
The page saysOne idea is that it follows the scent of ammonia and other waste from possible hosts, but that has not been proven.
The source saysIt is hypothesized that candiru track the scent of ammonia and other excretions from potential prey, although this has not been definitively proven.Note: Final pass: replaced 'likely uses a mix of chemical and visual cues'. ADW's chemical cue rests on this ammonia hypothesis, and Haddad 2021 (current) finds no robust evidence vandelliines react to ammonia, so the page states the hypothesis as unproven.
The page saysIts eyes are large, but it usually lives in cloudy water, so eyesight is probably not its main way to find one.
The source saysTheir eyes are quite large, which may indicate high visual acuity; however, candiru are typically found in turbid water where vision is limited, so eyesight is probably not the primary mode of host detection.
The page saysTiny and See-Through
The source saysCandiru are small, thin catfish. They have no scales and their bodies are transluscent
The page saysA candiru grows to 17 centimeters (6.7 inches) at most, and most are much smaller.
The source saysMaximum total length for this species is 17 cm, though most specimens are much smaller. ... 6.69 (high) inNote: 6.7 in rounds the source's 6.69 in
The page saysThe average is 5 centimeters (about 2 inches).
The source saysAverage length 5 cm 1.97 inNote: about 2 in rounds 1.97 in
The page saysIt has no scales, and its body is translucent, gaining color only after it feeds.
The source saysThey have no scales and their bodies are transluscent, becoming colored only after feeding.
The page saysIts mouth is lined with tiny needle-like teeth, and its large black eyes sit on top of its head.
The source saysbarbels near their mouths, which are lined with minute, needle-like teeth
The page saysits large black eyes sit on top of its head
The source sayslarge black eyes (relative to body size), which are placed on top of the head
The page saysShort spines on its gill covers face backward. They help keep it from being dislodged while it feeds.
The source saysCandiru have short, backward facing spines on their gill covers, which help to prevent it from being dislodged while feeding
The page saysCandiru live in the upper Amazon and Orinoco river basins of northern South America.
The source saysCandiru are found exclusively in the upper Amazon River and Orinoco River basins in northern South America.
The page saysThey live in shallow, slow-moving, acidic water with muddy or sandy bottoms.
The source saysCandiru live in shallow, slow moving, acidic waterways with muddy or sandy bottoms.
The page saysThey are found burrowed into the riverbed most of the time, coming out only to feed or mate
The source saysThese demersal fish can be found burrowed in the riverbed most of the time, only emerging to feed or mate.
The page saysand they feed by day as well as at night.
The source saysthey actively feed during the day as well as at night.
The page saysTheir hosts include the tambaqui, the golden dorado and the red-bellied piranha.
The source saysTambaqui ( Colossoma macropomum ) Amazonian pacu ( Piaractus brachypomus ) Red-bellied piranha ( Pygocentrus nattereri ) Golden dorado ( Salminus maxillosus )
The page saysTambaqui have been seen fighting back by tightening their gill covers and sweeping the parasites away with their fins.
The source sayshave been observed to exhibit defense mechanisms against candiru attacks, such as tightening their operculum and using their fins to sweep the parasites away.
The page saysCandiru very rarely kill a host, and hosts usually heal quickly after an attack.
The source saysThey very rarely kill their hosts, who usually heal quickly after an attack.
The page saysThe translucent, thin catfish that slips under a fish's gill cover and lets the host's own blood pressure fill its mouth.
The source saysit either forces itself under the operculum or waits for it to open naturally. ... The host's blood pressure pumps blood straight into the candiru's mouth
The page saysShallow, slow-moving waterways with muddy or sandy bottoms in the upper Amazon and Orinoco basins
The source saysCandiru are found exclusively in the upper Amazon River and Orinoco River basins in northern South America. ... Candiru live in shallow, slow moving, acidic waterways with muddy or sandy bottoms.
The page saysBlood of other fish, taken from arteries at the gills
The source saysCandiru are parasites, feeding on the blood of other fish. ... it heads towards the gills ... Once past the operculum, these parasites latch onto the ventral or dorsal aortal arteries.
The page saysGill-cover spines that hold it on while its host's blood pressure fills its mouth
The source saysOpercular spines help candiru stay attached to hosts' gills and aid in releasing blood. The host's blood pressure pumps blood straight into the candiru's mouth
The page saysAnimal Diversity Web notes that these parasites do not suck blood, as people once thought.
The source saysthese parasites do not "suck" blood as has been previously hypothesized
The page saysThe host fish's own blood pressure does the pumping, and spines on the candiru's gill covers help it stay attached.
The source saysOpercular spines help candiru stay attached to hosts' gills and aid in releasing blood. The host's blood pressure pumps blood straight into the candiru's mouth
The page saysA candiru tops out at 17 centimeters (6.7 inches), but most are much smaller, and the average length is 5 centimeters (about 2 inches).
The source saysMaximum total length for this species is 17 cm, though most specimens are much smaller. ... Range length 17 (high) cm 6.69 (high) in Average length 5 cm 1.97 inNote: 6.7 in and 2 in are roundings of the source's 6.69 and 1.97 in
The page saysa translucent catfish that stays burrowed in the riverbed and emerges only to feed
The source saysThese demersal fish can be found burrowed in the riverbed most of the time, only emerging to feed or mate.Note: Task #974: vibe.reason re-anchored on the burrow-and-feed cycle.
The page sayson a blood meal that usually lasts 30 to 145 seconds before it sinks back into the mud
The source saysThe length of a single blood meal is usually short, from 30-145 seconds. After feeding, candiru sink and burrow into the river bottom.
The page saysdangerLevel: Medium
The source saysIt is possible for candiru to parasitize humans, though this is very rare.Note: Task #974: Medium ('Can injure, but rarely seriously'), not Low: ADW lists 'injures humans' under negative impacts. Haddad 2021 calls the urethra cases disputed, so nothing supports a higher tier.

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.