{{Short description|Species of fishes}} {{Speciesbox | fossil_range = {{fossil range|15.5|0|Middle Miocene to present}} | image = Tambaqui Brésil (cropped).JPG | image_caption = | parent_authority = C. H. Eigenmann & C. H. Kennedy, 1903 | status = NT | status_system = IUCN3.1 | status_ref = <ref name="iucn status 28 October 2024">{{cite iucn |author= Brejão, G.L. |date=2024 |title=''Colossoma macropomum'' |volume=2024 |article-number=e.T49830760A85567354 |doi=10.2305/IUCN.UK.2024.RLTS.T49830760A85567354.en |access-date=28 October 2024}}</ref> | display_parents = 2 | taxon = Colossoma macropomum | authority = (G. Cuvier, 1818) | synonyms = *''Myletes macropomus'' <small>Cuvier, 1816</small> *''Myletes oculus'' <small>Cope, 1872</small> *''Myletes nigripinnis'' <small>Cope, 1878</small> *''Melloina tambaqui'' <small>Amaral Campos, 1946</small> }}
The '''tambaqui''' ('''''Colossoma macropomum''''') is a large species of freshwater fish in the family Serrasalmidae. It is native to tropical South America, but kept in aquaculture and introduced elsewhere.<ref name=fishbase>{{FishBase|genus=Colossoma|species=macropomum|year=2007|month=July}}</ref> It is also known by the names '''black pacu''', '''black-finned pacu''', '''giant pacu''', '''cachama''', '''gamitana''', and sometimes as '''pacu''' (a name used for several other related species).
The tambaqui is currently the only member of ''Colossoma'', but the ''Piaractus'' species were also included in this genus in the past.<ref>OPEFE (27 December 2011). [https://www.opefe.com/piaractus.html Genus Piaractus.] Retrieved 2 March 2017.</ref>
==Distribution== The tambaqui is native to freshwater habitats in the Amazon and Orinoco basins of tropical South America.<ref name=fishbase/> In nutrient-rich whitewater rivers such as the Madeira, Juruá, Putumayo (Içá) and Purus it ranges throughout, all the way up to their headwaters.<ref name=Lima2003>Araujo-Lima, C.A.R.M.; and M.L. Ruffino (2003). Migratory Fishes of the Brazilian Amazon. Pp. 233—302 in: Carolsfeld, J.; B. Harvey; C. Ross; and A. Baer (editors). Migratory Fishes of South America. {{ISBN|978-0968395820}}</ref> In nutrient-poor blackwater rivers such as the Rio Negro and clearwater rivers such as several rightbank tributaries of the Madeira it generally only occurs in the lower c. {{convert|300|km|mi|abbr=on|-2}} and is rare beyond the lowermost c. {{convert|150|km|mi|abbr=on|-2}}.<ref name=Lima2003/> It is widely kept in aquaculture outside its native range in South America.<ref name=fishbase/>
Middle Miocene-aged fossils of ''C. macropomum'' are known from northern Colombia and the Peruvian Amazon. Their occurrence in Colombia suggests that prior to further uplift of the Andes, they also inhabited western South America.<ref>{{Cite journal |last1=Ballen |first1=Gustavo A. |last2=Jaramillo |first2=Carlos |last3=Dagosta |first3=Fernando C. P. |last4=de Pinna |first4=Mario C. C. |date=2022 |title=A fossil fish assemblage from the middle Miocene of the Cocinetas Basin, northern Colombia |url=https://onlinelibrary.wiley.com/doi/abs/10.1002/spp2.1405 |journal=Papers in Palaeontology |language=en |volume=8 |issue=1 |article-number=e1405 |doi=10.1002/spp2.1405 |bibcode=2022PPal....8E1405B |issn=2056-2802|url-access=subscription }}</ref><ref>{{Cite journal |last1=Carrillo-Briceño |first1=Jorge D. |last2=Aguilera |first2=Orangel A. |last3=Benites-Palomino |first3=Aldo |last4=Hsiou |first4=Annie S. |last5=Birindelli |first5=José L. O. |last6=Adnet |first6=Sylvain |last7=Cadena |first7=Edwin-Alberto |last8=Scheyer |first8=Torsten M. |date=2021-12-20 |title=A historical vertebrate collection from the Middle Miocene of the Peruvian Amazon |journal=Swiss Journal of Palaeontology |language=en |volume=140 |issue=1 |page=26 |doi=10.1186/s13358-021-00239-7 |doi-access=free |bibcode=2021SwJP..140...26C |issn=1664-2384}}</ref> Their fossil range includes the modern Magdalena River basin, but modern occurrence in this river is due to introductions by humans.<ref name="Sleen2017">{{cite book |editor1=van der Sleen, P. |editor2=J.S. Albert | year=2017 | title=Field Guide to the Fishes of the Amazon, Orinoco, and Guianas | publisher=Princeton University Press | pages=182–183 | isbn=978-0-691-17074-9 }}</ref>
==Description== The tambaqui is the heaviest characin in the Americas (the lighter ''Salminus'' can grow longer) and the second heaviest scaled freshwater fish in South America (after the arapaima).<ref name=Goulding1982>{{cite journal | author1=Goulding, M. |author2=M.L. Carvalho | year=1982 | title=Life history and management of the tambaqui (''Colossoma macropomum'', Characidae): an important Amazonian food fish | journal=Revista Brasileira de Zoologia | volume=1 | issue=2 | pages=107–133 | doi=10.1590/S0101-81751982000200001 | doi-access=free }}</ref> It can reach up to {{cvt|1.1|m|ft}} in total length and {{cvt|44|kg|lboz}} in weight,<ref name=Sleen2017/> but a more typical size is {{cvt|0.7|m|ft}}.<ref name=fishbase/> The largest caught by rod-and-reel and recognized by IGFA weighed {{cvt|32.4|kg|lboz}},<ref>{{cite web|website=The International Game Fish Association|url=https://igfa.org/member-services/world-record/common-name/Tambaqui|title=Tambaqui (''Colossoma macropomum'')|access-date=9 March 2023}}</ref> although other systems have a {{cvt|37|kg|lboz}} fish caught in Peru in 2013.<ref>{{cite web|url=http://www.fishing-worldrecords.com/scientificname/Colossoma%20macropomum/show|title=''Colossoma macropomum'' {{!}} Black Pacu, Tambaqui |website=Fishing World Records.com e.U.}}</ref> After the flood season, around 10% of a tambaqui's weight is the visceral fat reserves and at least another 5% is fat found in the head and muscles.<ref name=Goulding1982/>
It is similar in shape to the piranha and juveniles are sometimes confused with the carnivorous fish; the tambaqui is tall and laterally compressed with large eyes and a slightly arched back. Unlike more predatory species, the teeth of the tambaqui are molar-like, an adaption for crushing plant seeds and nuts.<ref name=Goulding1982/> The lower half of its body is typically mainly blackish. The remaining is mainly gray, yellowish or olive, but the exact hue varies considerably and depends in part on habitat with individuals in blackwater being much darker than individuals from whitewater.<ref name=Goulding1982/> The pelvic, anal and small pectoral fins are black. The tambaqui resembles the red-bellied pacu (''Piaractus brachypomus''), but the latter species has a more rounded head profile (less elongated and pointed)<ref>{{cite journal|author=Cagauan, A.G |year=2007|title= Red-bellied Pacu in the Philippines|journal= Journal of Environmental Science and Management |volume=10|issue=1|pages= 42–47}}</ref> and a smaller adipose fin that lacks rays, as well as differences in teeth and operculum.<ref name=USGS>{{cite web|author=Nico, L.|author2= P. Fuller|author3= M. Neilson |date=22 October 2013|url=https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=418 |title=''Colossoma macropomum''|website= USGS Nonindigenous Aquatic Species Database |location=Gainesville, FL|access-date= 13 March 2017}}</ref><ref>{{cite book|author=Lauzanna, L.|author2= G. Loubens |year=1985 |title=Peces del Rio Marmoré|publisher= Editions de l'ORSTOM |isbn=2-7099-0779-8}}</ref>
Hybrids between the tambaqui and the similar ''Piaractus'' (both species) have been produced in aquaculture,<ref name=Gomes2012>{{cite journal|vauthors=Gomes, Schneider, Barros, Sampaio, Hashimoto, Porto-Foresti, Sampaio |url=http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652012000200020 |title=Innovative molecular approach to the identification of ''Colossoma macropomum'' and its hybrids|journal= An. Acad. Bras. Ciênc. |volume=84|issue=2|date= June 2012 |pages=517–526 |doi=10.1590/S0001-37652012005000025|pmid=22534749 |hdl=11449/8166 |hdl-access=free }}</ref> and are occasionally seen in the wild.<ref name=Sleen2017/> The hybrid offspring can be difficult to identify by appearance alone.<ref name=Gomes2012/><gallery mode="packed"> File:Replica of Pacu (Tambaqui) skull by Bone Clones.jpg|Skull replica at the San Diego Zoo File:Pacu shedd.jpg|At the Shedd Aquarium File:Tambaqui (Colossoma macropomum).jpg|At the Vancouver Aquarium File:TambaquiVeracrz.JPG|At the Aquarium of Veracruz </gallery>
==Ecology== thumb|Skull
===Habitat, breeding and migration=== [[File:US Washington Zoo 0605 051 (17187979858).jpg|thumb|At the National Zoological Park]] thumb|Preserved specimen thumb|Showing size [[File:Colossoma macropomum 205143907.jpg|thumb|In Carauari, Amazonas]] This species is mostly solitary,<ref name=fishbase/> but it migrates in large schools.<ref name=Goulding1982/> During the non-breeding season, adults stay in flooded forests of white (várzea), clear and blackwater (igapó) rivers.<ref name=fishbase/><ref name=Goulding1982/> They stay there for four to seven months during the flood season, but as the water level drops they move into the main river channels or to a lesser extent floodplain lakes.<ref name=Lima2003/><ref name=Goulding1982/> At the start of the next flood season, large schools move into whitewater rivers where they spawn between November and February.<ref name=Lima2003/><ref name=Goulding1982/> The exact spawning location in the whitewater rivers is not entirely certain, but apparently along woody shores<ref name=Lima2003/> or grassy levees.<ref name=Goulding1982/> The schools then break up as the adults return to the flooded forest of white, clear and blackwater rivers, and the annual pattern is repeated.<ref name=Lima2003/><ref name=Goulding1982/> Larvae are found in whitewater rivers, including the Amazon River itself.<ref name=Lima2003/> Juveniles stay near macrophytes in floodplains and flooded forests year-round, only switching to the adult migration pattern when reaching sexual maturity.<ref name=fishbase/><ref name=Lima2003/> Maturity is reached at a length of about {{convert|60|cm|ft|abbr=on|0}}.<ref name=Sleen2017/>
The species regularly reaches an age of 40 years and may reach up to 65.<ref name=Sleen2017/>
===Oxygen, salt and pH resistance=== When there is not enough oxygen in the river or lake, tambaqui obtain oxygen from the air. They are able to do this by their physical and inner body parts, such as their gills and swim bladder vascularization.<ref>{{cite journal|last1=Val|first1=A.L.|title=Oxygen-transfer in fish - Morphological and molecular adjustments|journal=Brazilian Journal of Medical and Biological Research|date=November–December 1995|volume=28|issue=11–12|pages=1119–1127|pmid=8728838}}</ref>
Tambaqui is a fish that lives in freshwater. Juveniles can survive in brackish water when the salinity is gradually raised. Salinity levels above 20 g/L result in death.<ref name=Fiuza2015>{{cite journal|last1=Siqueira Fiúza|first1=Luana|last2=Moraes Aragão|first2=Natália|last3=Ribeiro Junior|first3=Hermano Pinto|last4=Gazzineo de Moraes|first4=Manuella|last5=Castelo Branco Rocha|first5=Ítalo Régis|last6=Lustosa Neto|first6=Antônio Diogo|last7=Rocha de Sousa|first7=Rommel|last8=Malvino Madrid|first8=Raul Mário|last9=Gonçalves de Oliveira|first9=Elenise|last10=Farias Costa|first10=Francisco Hiran|title=Effects of salinity on the growth, survival, haematological parameters and osmoregulation of tambaqui ''Colossoma macropomum'' juveniles|journal=Aquaculture Research|date=March 2015|volume=46|pages=1–9|doi=10.1111/are.12224}}</ref> When juveniles are reared in salinities above 10 g/L, there is a significant detrimental effect on growth, haematological parameters and osmoregulation.<ref name=Fiuza2015/>
In an experiment, tambaqui had the pH of their water changed. No deaths occurred to tambaqui if the pH did not fall to 3.0. The only internal difference that was noted in tambaqui when the pH was being altered was a change in the acid-base of the plasma and red cells.<ref>{{cite journal|last1=Val|first1=Adalberto L|last2=Wood|first2=Chris M|last3=Wilson|first3=Rod W|last4=Gonzalez|first4=Richard J|last5=Patrick|first5=Marjorie L|last6=Bergman|first6=Harold L|title=Responses of an Amazonian Teleost, the Tambaqui (''Colossoma macropomum''), to Low pH in Extremely Soft Water|journal=Physiological Zoology|date=1998|volume=71|issue=6|pages=658–70|doi=10.1086/515977|pmid=9798253|url=http://repository.uwyo.edu/cgi/viewcontent.cgi?article=1010&context=zoology_facpub|hdl=20.500.11919/2945|s2cid=2337909|hdl-access=free}}{{Dead link|date=July 2025 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
In another experiment, tambaquis were exposed to pH drops from 6.0 to 4.0, similar to what they would encounter in their natural habitat. Researchers found that the microbial communities of the tambaqui fish gut were very resilient to the pH drops, which could explain part of the ability of tambaquis to migrate between black and white water streams in the Amazon.<ref>{{cite journal|last1=Sylvain|first1=François-Étienne|last2=Cheaib|first2=Bachar|last3=Correia|first3=Tiago Gabriel |last4= Llewellyn |first4= Martin J|last5=Fagundes|first5=Daniel L|last6=Val|first6=Adalberto Luis|last7=Derome|first7=Nicolas|title=pH drop impacts differentially skin and gut microbiota of the Amazonian fish tambaqui (''Colossoma macropomum'')|journal=Scientific Reports|volume=6|date=2016|issue=6|article-number=32032 |doi=10.1038/srep32032|pmid=27535789|pmc=4989189|bibcode=2016NatSR...632032S}}</ref>
===Diet=== [[File:Colossoma macropomum 118573606.jpg|thumb|Juvenile, in Bolivia]] Tambaqui consume fruits and seeds, especially from woody angiosperms and herbaceous species. Depending on the quantity and food quality of these foods, it causes the fish to decide on their location of their habitat.<ref name=Lucas2008>{{cite journal|last1=Lucas|first1=Christine M.|title=Within Flood Season Variation in Fruit Consumption and Seed Dispersal by Two Characin Fishes of the Amazon|journal=Biotropica|date=September 2008|volume=40|issue=5|pages=581–589|jstor=20492487|doi=10.1111/j.1744-7429.2008.00415.x|s2cid=85788776 |doi-access=free|bibcode=2008Biotr..40..581L }}</ref><ref>{{cite journal|last1=Reinaldo Castro|first1=Souza|last2=Bacconi Campeche|first2=Daniela Ferraz|last3=Campos|first3=R. M. L|last4=Figueiredo|first4=R. A. C. R|last5=Melo|first5=J. F. B|title= Frequência de alimentação para juvenis de tambaqui|journal= Arquivo Brasileiro de Medicina Veterinária e Zootecnia|date=June 2014|volume=66|issue=3|pages=927–932|doi=10.1590/1678-41625557|doi-access=free}}</ref> In one study during the high-water season, 78—98 percent of the diet consisted of fruits.<ref name=Lucas2008/> Another study of the stomach content of 138 specimens during the high-water season found that 44% of the weight was fruits and seeds, 30% was zooplankton and 22% was wild rice.<ref name=Goulding1982/> Among 125 specimens during the low-water season, a higher percentage had empty stomachs (14%, about ten times more than in the high-water season) and about 70% of the total stomach content weight was zooplankton.<ref name=Goulding1982/> In addition to seeds, fruits, wild rice and zooplankton, smaller levels of insects, snails, shrimps, small fish, filamentous algae and decaying plants are consumed.<ref name=fishbase/><ref name=Goulding1982/>
====Seed dispersal==== The tambaqui plays an important role in dispersing plant seeds.<ref name = "Cressey">{{Cite journal | last = Cressey | first = Daniel | title = Fruit-feasting fish fertilize faraway forests | journal = Nature News | publisher = Nature Publishing Group | date = 2011-03-23 | doi = 10.1038/news.2011.177}}</ref><ref name = "Yong">{{Cite web | last = Yong | first = Ed | title = Vegetarian piranhas are the Amazon's champion gardeners | work = Discover Magazine blogs | publisher = Kalmbach Publishing | date = 2011-03-22 | url = https://www.nationalgeographic.com/science/article/vegetarian-piranhas-are-the-amazons-champion-gardeners | archive-url = https://web.archive.org/web/20221207063450/https://www.nationalgeographic.com/science/article/vegetarian-piranhas-are-the-amazons-champion-gardeners | archive-date = December 7, 2022 | access-date = 2011-03-23|url-access=limited}}</ref><ref name = "Anderson">{{Cite journal | last = Anderson | first = J. T. |author2= Nuttle, T.|author3= Saldaña Rojas, J. S.|author4= Pendergast, T. H.|author5= Flecker, A. S. | title = Extremely long-distance seed dispersal by an overfished Amazonian frugivore | journal = Proc. R. Soc. B | volume = 278 | issue = 1710 | pages = 3329–3335| publisher = The Royal Society | date = 2011-03-23 | doi = 10.1098/rspb.2011.0155 | pmid = 21429923 | pmc =3177626}}</ref> The fruit seeds that fall in the water are consumed by tambaqui and the seed is dispersed somewhere else; this is similar to what birds do. This consumption includes about 35% of the trees and lianas during flood season and these seeds can grow after the floodwater calms down. Compared to the younger and smaller tambaqui, larger and older tambaqui are able to disperse the seeds in a faster rate.<ref>{{cite journal|last1=Anderson|first1=Jill T.|last2=Saldana Rojas|first2=Joe|last3=Flecker|first3=Alexander S.|title=High-quality seed dispersal by fruit-eating fishes in Amazonian floodplain habitats|journal=Oecologia|date=August 2009|volume=161|issue=2|pages=279–290|doi=10.1007/s00442-009-1371-4|pmid=19466459|jstor=40310200|bibcode=2009Oecol.161..279A|s2cid=1901361}}</ref> The gut of a well-fed {{convert|10|kg|lb|abbr=on}} tambaqui can contain more than {{convert|1|kg|lb|abbr=on}} seeds.<ref name=Sleen2017/> In general, more seeds are able to pass undamaged through the red-bellied pacu (''Piaractus brachypomus'') than the tambaqui, meaning that the former overall is a more efficient seed disperser.<ref name=Lucas2008/>
==Relationship to humans== right|thumb|A tambaqui for sale in the Manaus Fish Market, Brazil. This fish was approximately {{convert|85|cm|in|frac=2|abbr=on}} long. The meat of the tambaqui is popular and fetches top prices in fish markets in its native range.<ref name=Lima2003/> It is marketed fresh and frozen.<ref name=fishbase/>
Wild populations of the tambaqui have declined because of overfishing and many currently caught fish are juveniles.<ref name=Lima2003/> In Manaus alone, the landings fell from c. {{convert|15000|metric ton|-2}} per year in the 1970s to {{convert|800|metric ton}} in 1996.<ref name=Lima2003/> Based on a review by IBAMA, it was the 11th most caught fish by weight in the Brazilian Amazon in 1998 (just ahead of the closely related pirapitinga, ''Piaractus brachypomus'').<ref name=Lima2003/>
The tambaqui is now widely kept in aquaculture. It can live in oxygen-poor waters and is very resistant to diseases.<ref>{{cite journal|last1=Kochhann|first1=Daiani|last2=Jardim|first2=Manoela M.|last3=Valdez|first3=Domingos|last4=Fabiola|first4=Xochilt|last5=Adalberto|first5=Luis|title=Biochemical and behavioral responses of the Amazonian fish ''Colossoma macropomum'' to crude oil: The effect of oil layer on water surface|journal=Ecotoxicology and Environmental Safety|date=January 2015|volume=111|pages=32–41|doi=10.1016/j.ecoenv.2014.09.016|pmid=25450912|bibcode=2015EcoES.111...32K }}</ref> In Brazil, tambaqui is one of the main farmed fish species, and therefore important to the country's economy.<ref>{{cite journal|last1=Oeda Rodrigues|first1=Ana Paula|title=NUTRITION AND FEEDING OF TAMBAQUI (''Colossoma macropomum'')|journal=Boletim do Instituto de Pesca|date=2014|volume=40|issue=1|pages=135–145}}</ref> Studies of farmed tambaqui in Brazil have revealed a genetic diversity similar to that seen among wild populations.<ref>{{cite journal|last1=Aguiar|first1=Jonas|last2=Schneider|first2=Horacio|last3=Gomes|first3=Fatima|last4=Carneiro|first4=Jeferson|last5=Santos|first5=Simoni|last6=Rodrigues|first6=Luis R|last7=Sampaio|first7=Iracilda|title=Genetic variation in native and farmed populations of Tambaqui (''Colossoma macropomum'') in the Brazilian Amazon: regional discrepancies in farming systems|journal= Anais da Academia Brasileira de Ciências|date=December 2013|volume=85|issue=4|pages=1439–1447|doi=10.1590/0001-376520130007|pmid=24141412|doi-access=free}}</ref> In fish farms this species is sometimes hybridized with ''Piaractus'' to produce offspring that accept a wider temperature range (colder water) than pure tambaqui.<ref name=Gomes2012/>
In Thailand, this fish, known locally as ''pla khu dam'' (ปลาคู้ดำ), was introduced from Hong Kong and Singapore as part of fish-farming projects, but has adapted to local conditions and thrives in the wild in some areas.<ref>{{cite web|url=http://www.fao.org/fishery/introsp/3885/en|title=Colossoma macropomum|website=Fisheries and Aquaculture Division|publisher=Food and Agriculture Organization of the United Nations|location=Rome|year=2023|access-date=9 March 2023}}</ref> There is also an introduced population in Puerto Rico and singles (likely deliberate releases by aquarists) have been caught in a wide range of U.S. states,<ref name=USGS/> but only those in the warmest regions can survive.<ref name=seriouslyfish>{{cite web|website=SeriouslyFish |url=http://www.seriouslyfish.com/species/colossoma-macropomum/ |title=''Colossoma macropomum''|access-date= 13 March 2017}}</ref>
Juveniles {{convert|2-3|in|cm|abbr=on|disp=flip|round=0.5}} long, sometimes labelled as "vegetarian piranha", are frequently seen in the aquarium trade, but they rapidly grow to a large size and require an enormous tank.<ref name=seriouslyfish/>
==References== {{Reflist}}
{{Commons category-inline|Colossoma macropomum}}
{{Taxonbar|from1=Q261202|from2=Q2984442}}
Category:Colossomatinae Category:Freshwater fish of Brazil Category:Freshwater fish of Colombia Category:Fish of the Amazon basin Category:Fish described in 1818 Category:Taxa named by Georges Cuvier Category:Extant Miocene first appearances