Disclaimer:

The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

---

Common name: Arapaima

Synonyms and Other Names: Pirarucu (Brazil), Paiche (Peru, Ecuador) (Ferraris 2003).

Taxonomy: available through www.itis.gov

Identification: Arapaima, also known as Pirarucu, are large Neotropical fish with robust cylindrical bodies that become laterally compressed towards their posterior end (tail). Their heads are heavily sculptured with bony plates, and taper to a prominent lower jaw that protrudes upward. The mouth contains a bony structure that is covered in small griping teeth, which distinguishes the family, giving them the name bony tongue fishes (Ferraris 2003; Queiroz 2000). In the wild, juvenile Arapaima have a dark brown coloration, which beings to lighten as they age. Darker patches may be present on their dorsal surface, and red markings begin to appear on their posterior end becoming more prominent as they reach maturity (Queiroz 2000). Arapaima have large, heavily mineralized cycloid scales that form an armor-like exterior that protects them from predators such as Piranhas (Ferraris 2003; Queiroz 2000; Yang et al. 2014).

Until the work of Stewart (2013a), the genus Arapaima was thought to be monotypic, with Arapaima gigas considered as the only valid species (Castello and Stewart 2010; Hill and Lawson 2015). His reclassification of A. agassizii (Stewart 2013a), and description of new species (Stewart 2013b) uncovered hidden diversity within the genus, identifying a total of 5 distinct species. These species include A. gigas, A. mapae, A. arapaima, A. agassizii, and A. leptosome.  Stewart (2013a) and (2013b) present a detailed diagnosis of major morphological features that distinguish these 5 distinct Arapaima species.

Size: Arapaima are the largest freshwater fish in South America. They may reach a maximum length of 290 centimeters (cm) (Queiroz 2000; Ferraris 2003; Castello and Stewart 2010).

Native Range: The Arapaima is native to the Amazon River system of Brazil, southern Colombia, Amazonian Ecuador, and northeastern Peru; the Rio Tocantins basin in central Brazil; and the Essequibo River of Guyana (Ferraris 2003; Castello and Stewart 2010; Miranda-Chumacero et al. 2012; Hill, J.E. and Lawson, K.M., 2015). Castello and Stewart (2010) and Miranda-Chumacero et al. (2012) provide maps estimating the native distribution of Arapaima in Central America.

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Means of Introduction: While the exact vector is uncertain, introductions within the United States are likely the result of aquarium releases. Nonnative populations of Arapaima in foreign countries are known to have originated from fish that escaped aquaculture facilities (Miranda-Chumacero et al. 2012).

Impact of Introduction: In Bolivia, Arapaima gigas is suspected of having negatively impacted native fish populations, causing the decline of commercially valuable species (Van Damme 2006; Miranda-Chumacero et al. 2012; Hill and Lawson 2015). Fadjar et al. (2019) hypothesized that the establishment of A. gigas in the Brantas River, Indonesia, would result in negative economic and environmental impacts, but emphasized that a study examining this had not been completed.

References: (click for full references)

Arantes, C. C., L. Castello, D. J. Stewart, M. Certa, and H. L. Quieroz. 2010. Population density, growth and reproduction of Arapaima in an Amazonian river-floodplain. Ecology of Freshwater Fish 19:455–465.

Castello, L. 2008. Lateral migration of Arapaima gigas in floodplains of the Amazon. Ecology of Freshwater Fish 17(1):38-46.

Castello, L., and D.J. Stewart. 2010. Assessing CITES non-detriment findings procedures for Arapaima in Brazil. Journal of Applied Ichthyology 26(1):49-56.

Fadjar, M., R.A. Islamy, and E.Y. Herawati. 2019. First record of Arapaima gigas (Schinz, 1822) (Teleostei: Osteoglossomorpha), in the Brantas River, Sidoarjo, East Java, Indonesia. Biodiversitas Journal of Biological Diversity, 20(12).

Ferraris, C. J., Jr. 2003. Family Arapaimatidae (Bonytongues), p. 31. In: Check List of the Freshwater Fishes of South and Central America. R. E. Reis, S. O. Kullander, and C. J. Ferraris, Jr. (eds.). EDIPUCRS, Porto Alegre, Brazil.

Hrbek, T., I.P. Farias, M. Crossa, I. Sampaio, J.I. Porto, and A. Meyer. 2005. Population genetic analysis of Arapaima gigas, one of the largest freshwater fishes of the Amazon basin: implications for its conservation. Animal Conservation 8(3):297-308.

Hill, J.E., and K.M. Lawson. 2015. Risk screening of Arapaima, a new species proposed for aquaculture in Florida. North American Journal of Fisheries Management 35:885-894.

Miranda-Chumacero, G., R. Wallace, H. Calderón, G. Calderón, P. Willink, M. Guerrero, T.M. Siles, K. Lara, and D. Chuqui. 2012. Distribution of arapaima (Arapaima gigas) (Pisces: Arapaimatidae) in Bolivia: implications in the control and management of a non-native population. BioInvasions Record, 1(2).

Queiroz, H.L. 2000. Natural history and conservation of pirarucu, Arapaima gigas, at the Amazonian Várzea: red giants in muddy waters. Ph.D. Thesis. St. Andrews (UK): University of St. Andrews, 226 pp.

Stewart, D.J. 2013a. Re-description of the Arapaima agassizii (Valenciennes), a rare fish from Brazil (Osteoglossomorpha: Osteoglossidae). Copeia 1:38-51.

Stewart, D.J. 2013b. A new species of Arapaima (Osteoglossomorpha: Osteoglossidae) from the Solimões River, Amazonas State, Brazil. Copeia 3:470-476.

Yang, W., V. Sherman, B. Gludovatz, M. Mackey, E.A. Zimmermann, E.H. Chang, E. Schaible, Z. Qin, M.J. Buehler, R.O. Ritchie, and M.A. Meyers. 2014. Protective role of Arapaima gigas fish scales: structure and mechanical behavior. Acta biomaterialia 10(8):3599-3614.

Other Resources:
FishBase

Author: Procopio, J.

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.