# Arapaima Gigas (DD-684) > Arapaima gigas (pirarucu) is one of the largest freshwater fish in the world, native to the Amazon basin. FishBase gives a common length of about 2 m and maximum reports of 4.5 m and 200 kg. Very large historical records are poorly documented. It's an obligate air-breather. It uses a lung-like swim bladder and has to surface roughly every 5-15 minutes, which is a big part of why it has been easy to overfish. Its large overlapping scales have a hard mineralized outer layer over flexible layers of collagen fibers. Studies by Marc Meyers and colleagues found piranha teeth can't easily penetrate them. It feeds mainly on fish by suction, and birds or small animals are occasional prey. Taxonomy is unsettled. The genus Arapaima was long treated as a single species, but work by Donald Stewart (2013) revived and described additional species, such as A. leptosoma, so 'arapaima' doesn't always mean A. gigas. The IUCN lists A. gigas as Data Deficient. - Department: Nature - First published: 2025-12-26 - Last updated: 2025-12-26 - Permalink: https://detailenjoyer.com/case/arapaima-gigas/ - Author: Marcus Easterling (DetailEnjoyer), The Detail Department ## On the timeline - **2013**: Stewart revives and describes additional Arapaima species, such as A. leptosoma Full timeline: https://detailenjoyer.com/timeline/?case=arapaima-gigas ## Quick facts - **DD-684-F01**: The arapaima must surface to breathe air roughly every 5-15 minutes. _(Write-up · Exhibit B (It breathes air))_ - **DD-684-F02**: FishBase lists maximum reports of 4.5 m and 200 kg. _(Write-up · Exhibit A (Giant of the Amazon))_ ## Write-up Armor that beats piranhas. The Amazon's giant air-breathing fish. 1. **Giant of the Amazon**: FishBase lists a common length of about 2 m, with maximum reports of 4.5 m and 200 kg. Very large historical records are poorly documented. 2. **It breathes air**: The arapaima is an obligate air-breather. It uses a modified, lung-like swim bladder and surfaces roughly every 5-15 minutes. 3. **Piranha-proof scales**: Its scales combine a hard, mineralized outer layer with flexible layers of collagen fibers underneath. Research by Meyers and colleagues found piranha teeth can't easily bite through. 4. **Suction hunter**: It feeds mainly on fish, opening its mouth fast to suck prey in. Birds and other small animals are occasional prey. 5. **How many species?**: The genus was long treated as one species. Stewart (2013) described or revived additional species, such as A. leptosoma, and A. gigas is assessed by the IUCN as Data Deficient. ## Related case files - [Snake Supreme (DD-694)](https://detailenjoyer.com/case/snake-supreme/): Another South American giant - [Bos Gaurus (DD-685)](https://detailenjoyer.com/case/bos-gaurus/): Another species-name case - [Bathypterois grallator (DD-580)](https://detailenjoyer.com/case/bathypterois-grallator/): Another fish known by its scientific name ## Reel vs. record - **Size caveat**: a common adult length is about 2 m. 'Over 10 ft' (3 m+) is at the extreme end of the 4.5 m maximum FishBase lists, and very large records are poorly documented. - **Missing key fact**: it's an obligate air-breather that has to surface about every 5-15 minutes, which also makes it easy to harpoon and overfish. - **Diet emphasis**: it feeds mainly on fish. Birds and small mammals are occasional prey, not typical. - **Taxonomy**: Arapaima isn't a single species. Stewart (2013) recognized several, including A. leptosoma, so 'the arapaima' and Arapaima gigas aren't strictly the same thing. - **Missing status**: the IUCN lists A. gigas as Data Deficient, and wild populations have been heavily fished. ## Video: Arapaima Gigas: Armor That Beats Piranhas - Duration: 21.9 s · Published: 2025-12-26 - File: https://detailenjoyer.com/assets/videos/DSvaIyCAe0z.mp4 ### Transcript DID YOU KNOW? The arapaima is one of the largest freshwater fish on earth, native to the Amazon and its surrounding river systems, where it can grow over 10 ft long and weigh more than 400 lbs. Its body is armored with tough, mosaic-like scales that provide protection from predators such as piranhas, and it hunts with sudden powerful suction that can pull prey, including fish, birds, and even small mammals straight into its mouth. NOW YOU KNOW! ## Questions & answers **Q: How does the arapaima get most of its oxygen?** A: It's an obligate air-breather. _(Source: Write-up · Exhibit B (It breathes air) · FishBase: Arapaima gigas (Schinz, 1822); Wikipedia: Arapaima gigas)_ **Q: About how often must an arapaima surface?** A: Roughly every 5-15 minutes. _(Source: Write-up · Exhibit B (It breathes air) · FishBase: Arapaima gigas (Schinz, 1822); Wikipedia: Arapaima gigas)_ **Q: Which predator's teeth struggle to bite through arapaima scales?** A: Piranha. _(Source: Write-up · Exhibit C (Piranha-proof scales) · Wikipedia: Arapaima gigas)_ **Q: What does the arapaima mostly eat?** A: Mainly fish. _(Source: Write-up · Exhibit D (Suction hunter) · FishBase: Arapaima gigas (Schinz, 1822); Wikipedia: Arapaima gigas)_ **Q: What is the IUCN status of Arapaima gigas?** A: Data Deficient. _(Source: Write-up · Exhibit E (How many species?) · Stewart (2013), A new species of Arapaima from the Solimões River, Amazonas State, Brazil, Copeia; Neotropical Ichthyology: Integrative taxonomy data are reconciled around Arapaima gigas for the Brazilian Amazon; FishBase: Arapaima gigas (Schinz, 1822))_ ## Sources - [FishBase: Arapaima gigas (Schinz, 1822)](https://fishbase.se/summary/Arapaima-gigas.html) - [Stewart (2013), A new species of Arapaima from the Solimões River, Amazonas State, Brazil, Copeia](https://doi.org/10.1643/ci-12-017) - [Wikipedia: Arapaima gigas](https://en.wikipedia.org/wiki/Arapaima_gigas) - [Neotropical Ichthyology: Integrative taxonomy data are reconciled around Arapaima gigas for the Brazilian Amazon](https://www.scielo.br/j/ni/a/cDjT7VPC5m4yxnnLpBW95vw/?lang=en) ## Cite this case file Easterling, Marcus. "Arapaima Gigas." The Detail Department (DetailEnjoyer), case file DD-684, last updated Dec 26, 2025. https://detailenjoyer.com/case/arapaima-gigas/