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What the sources say

ArapaimaArapaima gigas

Every figure, record and mechanism on the Arapaima profile was written from a source, and this is the working table behind it: 57 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

Smithsonian's National Zoo and Conservation Biology Institute

Arapaima. Smithsonian's National Zoo and Conservation Biology Institute.

The page sayscan reach three meters
The source saysreaching up to 440 pounds (200 kilograms) and 10 feet (3 meters) in lengthNote: 3 meters written as 'three meters' for the tagline.
The page saysbreathes air through a lung-like swim bladder
The source saysit takes in air using a modified swim bladder that opens into the fish's mouth and acts as a lung
The page saysIts gills are so small that it takes in air using a modified swim bladder that opens into its mouth and acts as a lung
The source saysIts gills are so small that it takes in air using a modified swim bladder that opens into the fish's mouth and acts as a lung.
The page saysIt lives in slow-moving, typically oxygen-poor rivers of the Amazon River basin floodplain in Brazil, Peru and Guyana
The source saysThe arapaima is found in Brazil, Peru and Guyana. They live in the slow-moving and typically oxygen-deficient rivers of the Amazon River basin floodplain.
The page saysOut of the water, an arapaima can survive as long as 24 hours
The source saysIt can survive as long as 24 hours outside the water.
The page saysKnown in Brazil as pirarucu, a Tupi word that translates roughly as "red fish," and in Peru as paiche
The source saysIn Brazil, they are known as "pirarucu," a word from the Tupi language, which translates roughly as "red fish." In Peru, they are known as "paiche."
The page saysthe arapaima is possibly the largest freshwater fish in the world
The source saysThe arapaima is possibly the largest freshwater fish in the world
The page saysreaching up to 440 pounds (200 kilograms) and 10 feet (3 meters) long, though 200 pounds (90.7 kilograms) and 7 to 8 feet (2.2 to 2.4 meters) is more common
The source saysreaching up to 440 pounds (200 kilograms) and 10 feet (3 meters) in length. However, sizes of 200 pounds (90.7 kilograms) and 7 to 8 feet (2.2 to 2.4 meters) in length are more common.
The page saysIt can live up to 20 years
The source saysThe arapaima can live for up to 20 years.
The page saysAn arapaima feeds by opening its large mouth to create a vacuum that pulls in nearby food
The source saysby opening their large mouths they create a vacuum that pulls in nearby food objects
The page saysIt eats mostly fish but is also known to eat fruit, seeds, insects, and birds and mammals found on the surface of the water
The source saysthe arapaima eats mostly fish but is also known to eat fruits, seeds, insects, birds and mammals found on the surface of the water.
The page saysit can use short bursts of speed to attack prey hitting the surface
The source saysThey can also use short bursts of speed to attack potential prey hitting the surface of the water.
The page sayssharp, bony teeth, together with the teeth on the roof of its mouth, let it disable and shred its prey
The source saysTheir tongues and sharp, bony teeth, combined with the teeth on the roof of their palates, allow them to debilitate and shred their prey.
The page saysIts gills are so small that it takes in air using a modified swim bladder that opens into its mouth and acts as a lung.
The source saysIts gills are so small that it takes in air using a modified swim bladder that opens into the fish's mouth and acts as a lung.
The page saysIt can stay underwater for 10 to 20 minutes at a time
The source saysThis fish can breathe air and stay submerged for 10-20 minutes at a time.
The page saysit can survive as long as 24 hours out of the water
The source saysIt can survive as long as 24 hours outside the water.
The page saysSlow-moving, typically oxygen-poor rivers of the Amazon River basin floodplain in Brazil, Peru and Guyana
The source saysThe arapaima is found in Brazil, Peru and Guyana. They live in the slow-moving and typically oxygen-deficient rivers of the Amazon River basin floodplain.
The page saysMostly fish, but also known to eat fruit, seeds, insects, and birds and mammals found on the surface of the water
The source saysthe arapaima eats mostly fish but is also known to eat fruits, seeds, insects, birds and mammals found on the surface of the water.
The page saysA lung-like swim bladder for breathing air
The source saysa modified swim bladder that opens into the fish's mouth and acts as a lung
The page saysa fish of up to 200 kilograms
The source saysreaching up to 440 pounds (200 kilograms) and 10 feet (3 meters) in length

Source
02

Animal Diversity Web, University of Michigan

Arapaima gigas (arapaima). Animal Diversity Web, University of Michigan.

The page sayswhich means it has to breathe air: it needs to surface every 10 to 20 minutes
The source saysit is an obligate air breather that needs to surface every 10-20 minNote: Smithsonian agrees: 'stay submerged for 10-20 minutes at a time'.
The page saysand in floodplain lakes and flooded forest
The source saysA. gigas is found in several different types of habitat, such as the floodplain lakes of this region ... and the varzea or forest.Note: 'flooded' follows the Smithsonian: 'When the rivers overflow, fish can be dispersed into the surrounding forest for miles'.
The page saysIts bony or toothed tongue
The source saysA. gigas has a bony or toothed tongue
The page saysIt is bony or toothed, a feature that sets apart the fish in its order, the Osteoglossiformes
The source saysA. gigas has a bony or toothed tongue, which is the source of the title osteoglossomorph and a distinguishing character of those species in the order Osteoglossiformes
The page saysPeople have often used the pirarucu's bony tongue to scrape cylinders of dried guarana, an ingredient in a drink
The source saysthe pirarucu's bony tongue is often used to scrape cylinders of dried guarana, an ingredient in a beverageNote: Past tense because ADW's account dates from 2003.
The page saysplus floodplain lakes and flooded forest
The source saysA. gigas is found in several different types of habitat, such as the floodplain lakes of this region ... and the varzea or forest.
The page saysa bony or toothed tongue
The source saysA. gigas has a bony or toothed tongue
The page saysdangerLevel: Low
The source saysThere are no known adverse effects towards Homo sapiens.Note: Settle #396: Medium to Low; no source in the pack describes harm to people.
The page saysneeds to surface every 10 to 20 minutes to breathe
The source saysit is an obligate air breather that needs to surface every 10-20 min

Source
03

Lin et al. 2011

Lin et al. (2011). Mechanical properties and the laminate structure of Arapaima gigas scales. Journal of the Mechanical Behavior of Biomedical Materials.

The page saysmade of thin layers of collagen fibers
The source saysinternal lamellae with thickness of 50-60 μm each and composed of collagen fibers
The page saysThe fibers in each layer line up, but their direction changes from layer to layer, a twisted-plywood pattern called Bouligand stacking
The source saysThe alignment of collagen fibers is consistent in each individual layer but varies from layer to layer, forming a non-orthogonal plywood structure, known as Bouligand stacking.Note: 'twisted' follows mechanical-2013: 'Bouligand-type (twisted plywood)'.
The page saysIn hardness tests, the outer layer scored 550 megapascals (a unit of pressure), nearly three times the 200 megapascals of the inner layers
The source saysThe micro-indentation hardness of the external layer (550 MPa) is considerably higher than that of the internal layer (200 MPa)Note: 'nearly three times' is 550/200 = 2.75.
The page saysThe scales help protect this big fish against predators such as the piranha
The source saysThe Arapaima gigas scales play an important role in protecting this large Amazon basin fish against predators such as the piranha.
The page saysEach has a mineralized outer layer over thin inner layers of collagen fibers
The source saysThey have a laminate composite structure composed of an external mineralized layer and internal lamellae with thickness of 50-60 μm each and composed of collagen fibers
The page saysThe fibers line up within each layer, but their direction changes from layer to layer, a plywood-like pattern called Bouligand stacking
The source saysThe alignment of collagen fibers is consistent in each individual layer but varies from layer to layer, forming a non-orthogonal plywood structure, known as Bouligand stacking.
The page saysIn hardness tests the outer layer scored 550 megapascals, nearly three times the 200 megapascals of the inner layers
The source saysThe micro-indentation hardness of the external layer (550 MPa) is considerably higher than that of the internal layer (200 MPa)Note: 'nearly three times' is 550/200 = 2.75.

Source
04

Zimmermann et al. 2013

Zimmermann et al. (2013). Mechanical adaptability of the Bouligand-type structure in natural dermal armour. Nature Communications.

The page sayswears scale armor that resists piranhas
The source saysresist predation by piranhas through the strength and toughness of their scales, which act as natural dermal armour
The page saysArapaima resist attacks by piranhas thanks to their scales, which act as natural armor
The source saysresist predation by piranhas through the strength and toughness of their scales, which act as natural dermal armour
The page saysEach scale has a hard, mineralized outer shell around a softer core
The source saysArapaima scales consist of a hard, mineralized outer shell surrounding a more ductile core.Note: 'softer' rests on mechanical-2011's hardness figures (outer 550 MPa, inner 200 MPa), claimed below.
The page saysIn lab tests that pulled on scales, most of these layers turned toward the pull and stretched or slid, making the scale tougher and helping it avoid cracking
The source saysduring mechanical tensile tests ... most lamellae reorient towards the tensile axis and deform in tension through stretching/sliding mechanisms ... thereby enhancing the scale's ductility and toughness to prevent fracture.
The page saysscale armor that resists piranhas
The source saysresist predation by piranhas through the strength and toughness of their scales, which act as natural dermal armour

Source
05

Brauner et al. 2004

Brauner et al. (2004). Transition in organ function during the evolution of air-breathing; insights from Arapaima gigas, an obligate air-breathing teleost from the Amazon. Journal of Experimental Biology.

The page saysone of the most obligate air-breathing fishes alive
The source saysArapaima gigas is one of the most obligate extant air-breathing fishesNote: 'alive' renders 'extant'.

Source
06

Du et al. 2019

Du et al. (2019). The genome of the arapaima (Arapaima gigas) provides insights into gigantism, fast growth and chromosomal sex determination system. Scientific Reports.

The page saysgets up to 95 percent of its oxygen by breathing air
The source saysAs an obligate air-breathing fish obtaining up to 95% of its oxygen uptake by breathingNote: 'breathing' in the source is air breathing: the same sentence calls it an obligate air-breathing fish.
The page saysBreathing air lets it tolerate extremely low oxygen levels in the water
The source saysAs an obligate air-breathing fish obtaining up to 95% of its oxygen uptake by breathing, it is able to tolerate extremely low oxygen levels in the waterNote: The source's 'As an obligate air-breathing fish ... it is able to' is the link that 'lets' renders.
The page saysIn its first year a young arapaima can reach 10 to 15 kilograms, among the fastest growth rates recorded in fish
The source saysDuring the first year, juvenile arapaima exhibits the fastest growth rates recorded in fish, reaching weights between 10 to 15 kg

Source
07

Campos-Silva & Peres 2016

Campos-Silva & Peres (2016). Community-based management induces rapid recovery of a high-value tropical freshwater fishery. Scientific Reports.

The page saysBecause an arapaima comes to the surface often to breathe air, it is easier to spot and count directly
The source saysthereby frequently coming to the surface to breathe air, which facilitates direct sightings and counts
The page saysAlong Brazil's Juruá River, up to 20 trained fishermen per lake watched and listened for arapaima breathing
The source saysAlong the Juruá, this technique involved the collaborative participation of up to 20 previously trained and highly experienced arapaima fishermen per lake, who could detect air-breathing arapaima on the lake surface through both visual and acoustic cues
The page saysA 2016 study of 83 oxbow lakes along about 500 kilometers of the river
The source saysacross 83 oxbow lakes monitored along a ~500-km section of the Juruá River of Western Brazilian AmazoniaNote: 2016 is the paper's publication year (reference metadata).
The page saysprotected lakes, which local communities manage and close to fishing boats
The source saysProtected lakes are managed by local communities primarily as stock recovery and arapaima management sites, and exclude both commercial and subsistence fishing boats.
The page saysheld 304.8 arapaima on average, compared with only 9.2 in open-access lakes
The source saysAnnual population counts showed that protected lakes on average contained 304.8 (±332.5) arapaimas, compared to only 9.2 (±9.8) in open-access lakes.
The page saysThe counts went to IBAMA, Brazil's natural resources agency, which then authorized each lake a harvest of up to 30 percent of the adults counted, meaning fish longer than 1.5 meters
The source saysthe census data are forwarded to IBAMA (Brazilian Natural Resources Agency), which then authorizes a lake-specific harvest quota of up to 30% of all adults (>1.5 m in length) counted
The page saysprotected lakes could earn each community an average of US$10,601 a year, if the rules were followed and the full quota was caught
The source saysProtected lakes could derive total fishing revenues from arapaima stocks averaging US$10,601 ... every year, provided that full compliance with management rules takes place and total allowable catches (TACs) are harvestedNote: A modelled estimate per community (the abstract: 'average annual revenue of US$10,601 per community'), conditional on full compliance and the full quota.
The page saysAn arapaima comes to the surface often to breathe air, which makes it easier to spot and count directly
The source saysthereby frequently coming to the surface to breathe air, which facilitates direct sightings and counts
The page saysa 2016 study found that protected lakes held 304.8 arapaima on average, compared with only 9.2 in open-access lakes
The source saysAnnual population counts showed that protected lakes on average contained 304.8 (±332.5) arapaimas, compared to only 9.2 (±9.8) in open-access lakes.Note: 2016 is the paper's publication year (reference metadata).
The page saysBrazil's natural resources agency, IBAMA, used the counts to authorize each lake's harvest quota
The source saysthe census data are forwarded to IBAMA (Brazilian Natural Resources Agency), which then authorizes a lake-specific harvest quota of up to 30% of all adults (>1.5 m in length) counted

Source
08

The IUCN Red List of Threatened Species 1996

Arapaima gigas. The IUCN Red List of Threatened Species 1996: e.T1991A9110195.

The page saysThe IUCN Red List classes the arapaima as Data Deficient
The source saysIUCN Red List category: Data Deficient (DD). Arapaima gigas (Schinz, 1822), IUCN taxon 1991.Note: Current category from GBIF's copy of the Red List.
The page saysbased on an assessment made in 1996
The source saysIUCN Red List category: Data Deficient (DD). Arapaima gigas (Schinz, 1822), IUCN taxon 1991.Note: 1996 is the cited assessment's own year, in its DOI (iucn.uk.1996.rlts.t1991a9110195) and title, which audit:sources checks against Crossref; the taxon id 1991 matches GBIF's. Hand check: that no later assessment exists.

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.