View source for Guppy

{{Short description|Species of tropical fish}}
{{Other uses}}
{{Use dmy dates|date=April 2022}}
{{Speciesbox
| name = Guppy
| image = Guppy.jpg
| image_caption = male guppy
| genus = Poecilia
| species = reticulata
| status = LC
| status_system = IUCN3.1
| status_ref = <ref>{{cite journal |title=Poecilia reticulata: Lyons, T.J. |journal=[[IUCN Red List]] |doi=10.2305/IUCN.UK.2021-1.RLTS.T60444A3100119.en |year=2020 |s2cid=242029263 |doi-access=free }}</ref>
| authority = [[Wilhelm Peters|W. Peters]], 1859
| range_map = GuppyMAPA.gif
| range_map_caption = Distribution map for ''Poecilia reticulata''
| synonyms = *''Acanthocephalus guppii'' {{small|([[Albert Günther|Günther]], 1866)}}
*''Acanthophacelus reticulatus'' {{small|(W. Peters, 1859)}}
*''Girardinus guppii'' {{small|Günther, 1866}}
*''Girardinus reticulatus'' {{small|(W. Peters, 1859)}}
*''Lebistes poecilioides'' {{small|[[Filippo de Filippi|De Filippi]], 1861}}
*''Lebistes reticulatus'' {{small|(W. Peters, 1859)}}
''Poecilioides reticulatus'' {{small|(W. Peters, 1859)}}
| synonyms_ref = <ref>{{cite web |url=http://www.fishbase.org/Nomenclature/SynonymsList.php?ID=3228&GenusName=Poecilia&SpeciesName=reticulata |title=Synonyms of ''Poecilia reticulata'' |work=FishBase.org |access-date=16 November 2013 |archive-url=https://web.archive.org/web/20130922050250/http://www.fishbase.org/Nomenclature/SynonymsList.php?ID=3228&GenusName=Poecilia&SpeciesName=reticulata |archive-date=22 September 2013 |url-status=live}}</ref>
}}
The '''guppy''' ('''{{lang|la|Poecilia reticulata}}'''), also known as '''millionfish''' or the '''rainbow fish''',<ref>{{cite web |url=http://www.fishbase.org/comnames/CommonNamesList.php?ID=3228&GenusName=Poecilia&SpeciesName=reticulata |title=Common Names of ''Poecilia reticulata'' |work=FishBase.org |access-date=16 November 2013}}</ref> is one of the world's most widely distributed [[tropical fish]] and one of the most popular [[List of freshwater aquarium fish species|freshwater aquarium fish species]]. It is a member of the family [[Poeciliidae]] and, like almost all American members of the family, is [[live-bearing aquarium fish|live-bearing]].<ref>{{cite web |url=http://www.aquaticcommunity.com/livebearer/guppy.php |title=Guppy Fish |work=AquaticCommunity.com |access-date=24 February 2013 |archive-url=https://web.archive.org/web/20120609133734/http://www.aquaticcommunity.com/livebearer/guppy.php |archive-date=9 June 2012 |url-status=live}}</ref> Guppies originate from northeast South America, but have been introduced to many environments and are now found all over the world. They are highly adaptable and thrive in many different environmental and ecological conditions.<ref name="Magurran2005"/> Male guppies, which are smaller than females, have ornamental caudal and dorsal [[fish fin|fins]]. Wild guppies generally feed on a variety of food sources, including [[benthic zone|benthic]] [[algae]] and aquatic insect [[larva]]e.<ref name="Dussault1981"/> Guppies are used as a [[model organism]] in the fields of [[ecology]], [[evolution]], and [[behavioural studies]].<ref name="Magurran2005"/>

==Taxonomy==
Guppies were first described in Venezuela as ''Poecilia reticulata'' by [[Wilhelm Peters]] in 1859 and as ''Lebistes poecilioides'' in Barbados by [[Filippo de Filippi|De Filippi]] in 1861. It was named ''Girardinus guppii'' by [[Albert Günther]] in honor of [[Robert John Lechmere Guppy]], who sent specimens of the species from Trinidad to the [[Natural History Museum, London|Natural History Museum]] in London.<ref name="Gunther1866">{{cite book |url=https://books.google.com/books?id=7AkAAAAAQAAJ&pg=PA353 |title=Catalogue of the Fishes in the British Museum |publisher=Taylor and Francis |location=London |first=Albert |last=Günther |author-link=Albert Günther |volume=6 |page=353 |date=1866}}</ref> It was reclassified as ''Lebistes reticulatus'' by [[Charles Tate Regan|Regan]] in 1913. Then in 1963, Rosen and Bailey brought it back to its original name, ''Poecilia reticulata''. While the taxonomy of the species was frequently changed and resulted in many synonyms, "guppy" remains the common name even as ''Girardinus guppii'' is now considered a [[junior synonym]] of ''Poecilia reticulata''.<ref name="Magurran2005" />

==Distribution and habitat==
Guppies are native to [[Antigua and Barbuda]], [[Barbados]], [[Brazil]], [[Guyana]], [[Trinidad and Tobago]], and [[Venezuela]].<ref>{{cite web |url=http://www.fishbase.org/Country/CountryList.php?ID=3228&GenusName=Poecilia&SpeciesName=reticulata |title=Countries where ''Poecilia reticulata'' is found |work=FishBase.org |access-date=24 February 2010 |archive-url=https://web.archive.org/web/20130921171543/http://www.fishbase.org/country/CountryList.php?ID=3228&GenusName=Poecilia&SpeciesName=reticulata |archive-date=21 September 2013 |url-status=live}}</ref><ref>{{cite web |url=http://www.issg.org/database/species/ecology.asp?si=683 |title=''Poecilia reticulata'' (fish) |work=Global Invasive Species Database |date=27 October 2006 |access-date=27 August 2010 |archive-url=https://web.archive.org/web/20130921054959/http://www.issg.org/database/species/ecology.asp?si=683 |archive-date=21 September 2013 |url-status=live}}</ref> However, guppies have been introduced to many different countries on every continent except Antarctica. Sometimes this has occurred accidentally, but most often as a means of [[mosquito]] control. The guppies were expected to eat the mosquito [[larva]]e and help slow the spread of [[malaria]], but in many cases, these guppies have had a [[invasive species|negative impact]] on native fish populations.<ref>{{FishBase |genus=Poecilia |species=reticulata |month=April |year=2007}}</ref> Field studies reveal that guppies have colonized almost every freshwater body accessible to them in their natural ranges, especially in the streams located near the coastal fringes of mainland South America. Although not typically found there, guppies also have tolerance to [[brackish water]] and have colonized some brackish environments.<ref name="Magurran2005" /> They tend to be more abundant in smaller streams and pools than in large, deep, or fast-flowing rivers.<ref name="MagurranPhillip 2001">{{cite journal |title=Evolutionary implications of large-scale patterns in the ecology of Trinidadian guppies, ''Poecilia reticulata'' |journal=[[Biological Journal of the Linnean Society]] |first1=Anne E. |last1=Magurran |first2=Dawn A. T. |last2=Phillip |volume=73 |pages=1–9 |year=2001 |issue=1 |doi=10.1006/bijl.2000.0519|doi-access=free |bibcode=2001BJLS...73....1M }}</ref> They also are capable of being acclimated to full saltwater like their [[Poecilia|molly]] cousins.

==Description==
[[File:Guppy CS pair 4 20130113.jpg|thumb|left|Sexual polymorphism exhibited in the Trinidadian guppy (above male, below female)]]
[[File:Guppy breeds.jpg|thumb|Guppy breeds]]
Guppies exhibit [[sexual dimorphism]]. While wild-type females are grey in body colour, males have splashes, spots, or stripes that can be any of a wide variety of colors.<ref>{{cite web |url=http://www.seriouslyfish.com/species/poecilia-reticulata/ |title=''Poecilia reticulata'': Guppy |work=SeriouslyFish.com |access-date=24 February 2013 |archive-date=19 October 2013 |archive-url=https://web.archive.org/web/20131019122254/http://www.seriouslyfish.com/species/poecilia-reticulata/ |url-status=live}}</ref> The development and exhibiting of color patterns in male guppies is usually due to the amount of thyroid hormone that they contain. The thyroid hormones not only influence color pattern, but control endocrine function in response to their environment.<ref>{{cite journal |last1=Prazdnikov |first1=Denis V. |title=Role of thyroid hormones in color diversity of male guppies: experimental data on Endler's guppy (Poecilia wingei) |journal=Environmental Biology of Fishes |date=28 May 2021 |volume=104 |issue=June 2021 |pages=675–688 |doi=10.1007/s10641-021-01102-x|bibcode=2021EnvBF.104..675P |s2cid=236416650 }}</ref> Guppies vary in size depending on their gender. Male guppies are typically 1.5–4 cm (0.6–1.6 inches) long, while female guppies are larger, usually 3–7 cm (1.2–2.8 inches) long.

A variety of [[animal fancy|fancy]] guppy strains are produced by breeders through [[selective breeding]], characterized by different colours, patterns, shapes, and sizes of fins, such as snakeskin and grass varieties. Many domestic strains have morphological traits that are very distinct from the wild-type antecedents. Males and females of many domestic strains usually have larger body size and are much more lavishly ornamented than their wild-type antecedents.<ref>{{cite web |url=http://www.viviparos.com/Fichas/P%20reticulata%20eng.htm |title=''Poecilia reticulata'' Peters, 1860 |work=Viviparos.com |access-date=18 November 2013 |archive-url=https://web.archive.org/web/20120119111057/http://www.viviparos.com/Fichas/P%20reticulata%20eng.htm |archive-date=19 January 2012 |url-status=live}}</ref>

Guppies have 23 pairs of [[chromosome]]s, including one pair of [[sex chromosomes]], the same number as humans.<ref name="Khoo1999">{{cite journal |title=Genetic Basis of the Variegated Tail Pattern in the Guppy, ''Poecilia reticulata'' |journal=[[Zoological Science]] |first1=Gideon |last1=Khoo |first2=Tit Meng |last2=Lim |first3=Woon-Khiong |last3=Chan |first4=Violet P. E. |last4=Phang |volume=16 |issue=3 |pages=431–437 |year=1999 |doi=10.2108/zsj.16.431|s2cid=73606453 |doi-access=free }}</ref> The genes responsible for male guppies' ornamentations are [[Y linkage|Y-chromosome linked]] and are [[heritability|heritable]].<ref name="Brooks">{{cite journal |title=Negative genetic correlation between male sexual attractiveness and survival |journal=[[Nature (journal)|Nature]] |first=Robert |last=Brooks |volume=406 |issue=6791 |pages=67–70 |year=2000 |doi=10.1038/35017552|pmid=10894542 |bibcode=2000Natur.406...67B |s2cid=4385649 }}</ref>

==Lifecycle==
[[File:Guppy Poecilia reticulata.jpg|alt=guppy|thumb|Guppy (female)]]
Two generations of guppies per year occur in the wild. Guppies are well developed and capable of independent existence without further parental care by the time they are born. Young guppies [[shoaling and schooling|school]] together and perform [[anti-predator tactics]]. Brood size is extremely variable, yet some consistent differences exist among populations depending on the [[predation]] level and other factors.<ref name="Magurran2005" /> Females of matching body sizes tend to produce more numerous but smaller-sized offspring in high-predation conditions. Female guppies first produce offspring at 10–20 weeks of age, and they continue to reproduce until 20–34 months of age. Male guppies mature in 7 weeks or less.<ref name="Magurran2005" /> Total lifespan of guppies in the wild varies greatly, but it is typically around 2 years.<ref name="Reznick2006" /> Variations in such [[life history theory|life historic characteristics]] of guppies are observed in different populations, indicating that different [[evolutionary pressure]]s exist.
[[File:Guppy coppia gialla.jpg|thumb|Female (left) and male (right) guppies, an ornamental aquarium strain]]

===Maturity===
Guppies' body sizes are positively correlated with age, and their size at maturation varies highly depending on the predation risk of the occupied environments. Male and female guppies from high-predation regions mature faster and start reproducing earlier, and they devote more resources to reproduction than those from low-predation regions.<ref name="Reznick1996">{{cite journal |title=Life-History Evolution in Guppies (''Poecilia reticulata'') 6. Differential Mortality as a Mechanism for Natural Selection |journal=[[Evolution (journal)|Evolution]] |first1=David N. |last1=Reznick |first2=Mark J. IV |last2=Butler |first3=F. Helen |last3=Rodd |first4=Patrick |last4=Ross |volume=50 |issue=4 |pages=1651–1660 |year=1996 |jstor=2410901 |doi=10.2307/2410901|pmid=28565709 }}</ref> Females from high-predation regions reproduce more frequently and produce more offspring per litter, indicating that they are more [[fecundity|fecund]] than low-predation females. Female guppies' reproductive success is also related to age. Older females produce offspring with reduced size and at increased interbrood intervals.<ref name="Reznick2001">{{cite journal |title=The evolution of senescence in natural populations of guppies (''Poecilia reticulata''): a comparative approach |journal=Experimental Gerontology |first1=David N. |last1=Reznick |first2=G. |last2=Buckwalter |first3=J. |last3=Groff |first4=D. |last4=Elder |volume=36 |issue=4–6 |pages=791–812 |year=2001 |doi=10.1016/S0531-5565(00)00241-2 |pmid=11295514|s2cid=23359090 }}</ref>

===Senescence===
One major factor that affects wild guppies' [[senescence]] patterns is the mortality rate caused by predation. Guppies from high-predation environments suffer high extrinsic mortality rate because they are more likely to be killed by predators. Female guppies from high-predation environments experience a significant increase in mortality at 6 months of age, while those from low-predation environments do not suffer increased mortality until 16 months. However, guppies from high-predation environments were found to have longer lifespans because their reproductive lifespans are longer. No significant difference is seen in postreproductive lifespans.<ref name="Reznick2006">{{cite journal |title=The Evolution of Senescence and Post-Reproductive Lifespan in Guppies (''Poecilia reticulata'') |journal=[[PLOS Biology]] |first1=David N. |last1=Reznick |first2=Michael |last2=Bryant |first3=Donna |last3=Holmes |volume=4 |issue=1 |pages=136–143 |year=2006 |doi=10.1371/journal.pbio.0040007 |pmid=16363919 |pmc=1318473 |doi-access=free }}</ref>{{dubious|date=May 2020}}

===Population regulations===
In addition to senescence pattern, resource availability and density also matter in regulation of guppy populations. Guppies reduce their fecundity and reproductive allocation in response to scarce food. When food is abundant, they increase brood size.<ref name="Reznick1983">{{cite journal |title=The Structure of Guppy Life Histories: The Tradeoff between Growth and Reproduction |journal=[[Ecology (journal)|Ecology]] |first1=David N. |last1=Reznick |volume=64 |issue=4 |pages=862–873 |year=1983 |doi=10.2307/1937209|jstor=1937209 |bibcode=1983Ecol...64..862R }}</ref> Differential reproductive allocation can be the cause of seasonality of life-history characteristics in some guppy populations. For example, during the wet season from May to December, guppies in the [[Northern Range]] of Trinidad reduce their investment in reproduction regardless of predation level, possibly in response to decreased food resources.<ref name="Reznick1989">{{cite journal |title=Life-History Evolution in Guppies: 2. Repeatability of Field Observations and the Effects of Season on Life Histories |journal=[[Evolution (journal)|Evolution]] |first1=David N. |last1=Reznick |volume=43 |issue=6 |pages=1285–1297 |year=1989 |jstor=2409363 |doi=10.2307/2409363|pmid=28564499 }}</ref> Population density also matters in simpler environments because higher [[intraspecific competition]] causes a decrease in reproductive rate and [[somatic (biology)|somatic]] growth rate, and a corresponding increase in [[Juvenile (organism)|juvenile]] mortality rate due to cannibalism.<ref name="Barlow1992">{{cite journal |title=Nonlinear and Logistic Growth in Experimental Populations of Guppies |journal=[[Ecology (journal)|Ecology]] |first1=Jay |last1=Barlow |volume=73 |issue=3 |pages=941–950 |year=1992 |doi=10.2307/1940170|jstor=1940170 |bibcode=1992Ecol...73..941B |s2cid=51902589 }}</ref> It was confirmed that in low-predation environments, guppy populations are in part regulated by density.<ref name="Bronikowski2002">{{cite journal |title=Population-Dynamic Consequences of Predator-Induced Life History Variation in the Guppy (''Poecilia reticulata'') |journal=[[Ecology (journal)|Ecology]] |first1=Anne M. |last1=Bronikowski |first2=Mark E. |last2=Clark |first3=F. Helen |last3=Rodd |first4=David N. |last4=Reznick |volume=83 |issue=8 |pages=2194–2204 |year=2002 |jstor=3072051 |doi=10.2307/3072051}}</ref>

==Ecology and behavior==

===Mating===
Guppies have the mating system called [[polyandry in fish|polyandry]], where females mate with multiple males.<ref name="Barbosa">{{cite journal |title=Evidence of female-promoted polyandry in Trinidadian guppies |journal=Environmental Biology of Fishes |first1=Miguel |last1=Barbosa |first2=Anne E. |last2=Magurran |volume=90 |issue=1 |pages=95–102 |year=2011 |doi=10.1007/s10641-010-9721-y|bibcode=2011EnvBF..90...95B |s2cid=27300353 }}</ref> Multiple mating is beneficial for males because the males' reproductive success is directly related to how many times they mate. The cost of multiple mating for males is very low because they do not provide material benefit to the females or parental care to the offspring. Conversely, multiple mating can be disadvantageous for females because it reduces [[foraging]] efficiency and increases the chances of predation and parasitic infection.<ref name="Evans2000" /> However, females gain some potential benefits from multiple mating. For example, females that mate multiple times are found to be able to produce more offspring in shorter [[gestation]] time, and their offspring tend to have better qualities such as enhanced [[Shoaling and schooling|schooling]] and predator evasion abilities.<ref name="Evans2000">{{cite journal |title=Multiple benefits of multiple mating in guppies |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |first1=J. P. |last1=Evans |first2=Anne E. |last2=Magurran |volume=97 |issue=18 |pages=10074–10076 |year=2000 |pmc=27698 |pmid=10954750 |doi=10.1073/pnas.180207297|bibcode=2000PNAS...9710074E |doi-access=free }}</ref>

Female guppies mate again more actively and delay the development of a brood when the anticipated second mate is more attractive than the first male. Experiments show that remating females prefer a novel male to the original male or a brother of the original male with similar [[phenotype]]s. Females' preference for novel males in remating can explain the excessive phenotypic [[polymorphism (biology)|polymorphism]] in male guppies.<ref name="Eakley2004">{{cite journal |title=Possible role of female discrimination against 'redundant' males in the evolution of colour pattern polymorphism in guppies |journal=[[Proceedings of the Royal Society B]] |first1=Angela L. |last1=Eakley |first2=Anne E. |last2=Houde |volume=271 |issue=Suppl 5 |pages=S299–S301 |year=2004 |pmc=1810072 |pmid=15504000 |doi=10.1098/rsbl.2004.0165}}</ref>

====Inbreeding avoidance====
[[Inbreeding]] ordinarily has negative fitness consequences ([[inbreeding depression]]), and as a result species have evolved mechanisms to avoid inbreeding.  Inbreeding depression is considered to be due largely to the expression of [[homozygous]] deleterious [[recessive]] mutations.<ref name="pmid19834483">{{cite journal |title=The genetics of inbreeding depression |journal=Nature Reviews Genetics |first1=Deborah |last1=Charlesworth |first2=John H. |last2=Willis |volume=10 |issue=11 |pages=783–96 |date=November 2009 |pmid=19834483 |doi=10.1038/nrg2664|s2cid=771357 }}</ref> Numerous inbreeding avoidance mechanisms operating prior to mating have been described.  However, inbreeding avoidance mechanisms that operate subsequent to copulation are less well known.  In guppies, a post-copulatory mechanism of inbreeding avoidance occurs based on competition between sperm of rival males for achieving fertilization.<ref name="Fitzpatrick2014">{{cite journal |title=Postcopulatory inbreeding avoidance in guppies |journal=Journal of Evolutionary Biology |first1=J. L. |last1=Fitzpatrick |first2=J. P. |last2=Evans |volume=27 |issue=12 |pages=2585–94 |date=December 2014 |pmid=25387854 |doi=10.1111/jeb.12545|s2cid=934203 |url=https://api.research-repository.uwa.edu.au/files/7422919/Fitzpatrick_and_Evans_PC_inbreeding_WITHOUT_CHANGES_TRACKED.pdf |doi-access=free }}</ref> In competitions between sperm from an unrelated male and from a full sibling male, a significant bias in paternity towards the unrelated male was observed.<ref name="Fitzpatrick2014" />

====Females' mating choice====
Female guppy choice plays an important role in multiple mating. Female guppies are attracted to brightly colored males, especially ones with orange spots on the flank.<ref name="Houde1988">{{cite journal |title=Genetic difference in female choice between two guppy populations |journal=[[Animal Behaviour (journal)|Animal Behaviour]] |first=Anne E. |last=Houde |volume=36 |issue=2 |pages=511–516 |date=April 1988 |doi=10.1016/S0003-3472(88)80022-8|s2cid=53157095 }}</ref> Orange spots can serve as an indicator of better physical fitness, as orange-spotted males are observed to swim longer in a strong current.<ref name="Nicoletto1991">{{cite journal |title=The relationship between male ornamentation and swimming performance in the guppy, ''Poecilia reticulata'' |journal=[[Behavioral Ecology and Sociobiology]] |first=Paul F. |last=Nicoletto |volume=28 |issue=5 |pages=365–370 |date=June 1991 |doi=10.1007/BF00164386|bibcode=1991BEcoS..28..365N |s2cid=22006110 }}</ref> There is also the concept of color association to possibly explain [[mate choice]] since one of the food sources wild guppies compete vigorously for is the fruit of cabrehash trees (''[[Sloanea]] laurifolia''), an orange [[carotenoid]]-containing fruit.<ref name="Cole201504">{{cite journal |title=Artificial selection for food colour preferences |journal=Proceedings of the Royal Society B: Biological Sciences |first1=Gemma L. |last1=Cole |first2=John A. |last2=Endler |volume=282 |issue=1804 |at=20143108 |date=7 April 2015 |doi=10.1098/rspb.2014.3108 |pmc=4375879 |pmid=25740894}}</ref> The orange coloration that female guppies select for in males is composed of carotenoids, the [[colorfulness|saturation]] of which is affected by the male's carotenoid ingestion and parasite load.<ref name="Rodd200203">{{cite journal |title=A possible non-sexual origin of mate preference: are male guppies mimicking fruit? |journal=Proceedings of the Royal Society B: Biological Sciences |first1=F. Helen |last1=Rodd |first2=Kimberly A. |last2=Hughes |first3=Gregory F. |last3=Grether |first4=Colette T. |last4=Baril |volume=269 |issue=1490 |pages=475–481 |date=7 March 2002 |doi=10.1098/rspb.2001.1891 |pmc=1690917 |pmid=11886639}}</ref> Guppies cannot synthesize these pigments by themselves and must obtain them through their diet. Because of this connection, females are possibly selecting for healthy males with superior foraging abilities by choosing mates with bright orange carotinoid pigments, thus increasing the survival chance of her offspring.<ref name="Rodd200203" /> Due to the advantage in mating, male guppies evolve to have more ornamentation across generations in low-predation environments where the cost of being conspicuous is lower. The rate and duration of [[courtship display]] of male guppies also play an important role in female guppies' mating choice. Courtship behavior is another indicator of fitness due to the physical strength involved in maintaining the courtship dance, called sigmoid display, in which the males flex their bodies into an ''S'' shape and vibrate rapidly.<ref name="Nicoletto1996">{{cite journal |title=The influence of water velocity on the display behavior of male guppies, ''Poecilia reticulata'' |journal=[[Behavioral Ecology (journal)|Behavioral Ecology]] |first=Paul F. |last=Nicoletto |volume=7 |issue=3 |pages=272–278 |year=1996 |doi=10.1093/beheco/7.3.272|doi-access=free }}</ref> [[File:Sigmoid Display of Male Guppy Fish.png|thumb|Sigmoid display of male guppy]]

Female mating choice may also be influenced by another female's choice. In an experiment, female guppies watched two males, one solitary and the other actively courting another female, and were given a choice between the two. Most females spent a longer time next to the male that was courting.<ref name="Dugatkin1992">{{cite journal |title=Sexual selection and imitation: Females copy the mate choice of others |journal=[[The American Naturalist]] |first1=L. A. |last1=Dugatkin |volume=139 |issue=6 |pages=1384–1389 |year=1992 |doi=10.1086/285392|s2cid=84747983 }}</ref> Female guppies' preference for fit males allows their descendants to inherit better physical fitness and better chance of survival.

===Predation===
[[File:Aequidens pulcher.jpg|thumb|''Aequidens pulcher'', a common predator of guppies]]
Guppies have many predators, such as larger fish and birds, in their native range. Some of their common predators in the wild are ''[[Crenicichla|Crenicichla alta]]'', ''[[Anablepsoides|Anablepsoides hartii]]'', and ''[[blue acara|Aequidens pulcher]]''.<ref>{{cite web |url=https://www.pbs.org/wgbh/evolution/sex/guppy/predators.html |title=Sex and the single guppy |work=PBS |access-date=6 December 2013 |archive-url=https://web.archive.org/web/20131212104816/http://www.pbs.org/wgbh/evolution/sex/guppy/predators.html |archive-date=12 December 2013 |url-status=live}}</ref> Guppies' small bodies and the bright coloration of males make them easy prey, and like many fish, they often school together to avoid predation. Schooling is more favored by evolution in populations of guppies under high predation pressure, exerted either by predator type or predator density.<ref name="Seghers1974">{{cite journal |title=Schooling Behavior in the Guppy (''Poecilia reticulata''): An Evolutionary Response to Predation |journal=[[Evolution (journal)|Evolution]] |first=Benoni H. |last=Seghers |volume=28 |issue=3 |pages=486–489 |date=September 1974 |jstor=2407174 |doi=10.2307/2407174|pmid=28564850 }}</ref> Male guppies rely on schooling, in particular the behavioral responses of females, to make antipredator decisions.<ref>{{Cite journal |last1=Brusseau |first1=Alix J P |last2=Feyten |first2=Laurence E A |last3=Crane |first3=Adam L |last4=Ramnarine |first4=Indar W |last5=Ferrari |first5=Maud C O |last6=Brown |first6=Grant E |date=2024-08-07 |title=Antipredator decisions of male Trinidadian guppies ( Poecilia reticulata ) depend on social cues from females |journal=Current Zoology |language=en |doi=10.1093/cz/zoae040 |issn=1674-5507|doi-access=free }}</ref> Coloration of guppies also evolves differentially in response to predation. Male guppies that are brighter in color have an advantage in mating as they attract more females in general, but they have a higher risk of being noticed by predators than duller males. Male guppies evolve to be more dull in color and have fewer, smaller spots under intense predation both in wild and in laboratory settings.<ref name="Endler1980">{{cite journal |title=Natural Selection on Color Patterns in ''Poecilia reticulata'' |journal=[[Evolution (journal)|Evolution]] |first=John A. |last=Endler |volume=34 |issue=1 |pages=76–91 |date=January 1980 |jstor=2408316 |doi=10.2307/2408316 |pmid=28563214}}</ref> Female guppies in a high-predation environment also evolve to prefer brightly colored males less, often rejecting them.<ref name="Stoner1988">{{cite journal |title=Phenotypic differentiation in female preference related to geographic variation in male predation risk in the Trinidad guppy (''Poecilia reticulata'') |journal=[[Behavioral Ecology and Sociobiology]] |first1=Gregory |last1=Stoner |first2=Felix |last2=Breden |volume=22 |issue=4 |pages=285–291 |date=April 1988 |doi=10.1007/BF00299844|bibcode=1988BEcoS..22..285S |s2cid=24521306 }}</ref>

====Predator inspection====
When guppies encounter a potential predator, some of them approach the predator to assess danger. This behavior, called predator inspection, benefits the inspector since it gains information, but puts the inspector at a risk of predation. To reduce the risk, inspectors avoid the predator's mouth area—called the 'attack cone'—and approach the predator from the side or back. They may also form a group for protection, the size of which is larger in high-predation populations. Although evidence indicates predators are less likely to attack an inspector than a non-inspector, the inspectors remain at higher risk due to proximity to the predator.<ref name="Magurran1990">{{cite journal |title=Population differences in predator recognition and attack cone avoidance in the guppy ''Poecilia reticulata'' |journal=[[Animal Behaviour (journal)|Animal Behaviour]] |first1=Anne E. |last1=Magurran |first2=Benoni H. |last2=Seghers |volume=40 |issue=3 |pages=443–452 |date=September 1990 |doi=10.1016/S0003-3472(05)80524-X|s2cid=53258954 }}</ref>

Risk-taking behaviors such as predator inspection can be evolutionarily stable only when a mechanism prevents selfish individuals from taking advantage of "altruistic" individuals. Guppies may adopt a conditional-approach strategy that resembles [[tit for tat]]. According to this hypothesis, guppies would inspect the predator on the first move, but if their co-inspectors do not participate in the predator inspection visits or do not approach the predator close enough, they can retaliate by copying the defector's last move in the next predator inspection visit. The hypothesis was supported in laboratory experiments.<ref name="Dugatkin1991">{{cite journal |title=Tit-For-Tat in guppies (''Poecilia reticulata''): the relative nature of cooperation and defection during predator inspection |journal=Evolutionary Ecology |first1=Lee A. |last1=Dugatkin |first2=Michael |last2=Alfieri |volume=5 |issue=3 |pages=300–309 |date=July 1991 |doi=10.1007/BF02214234|bibcode=1991EvEco...5..300D |s2cid=23482076 }}</ref>

====Predator diversion====
When guppies detect a predator, their irises rapidly darken from silver to jet black, which draws predators to attack the guppies' head instead of their body's center of mass.<ref name="A Matador-like Predator Diversion S">{{cite journal |last1=Heathcote |first1=Robert J. P. |last2=Troscianko |first2=Jolyon |last3=Darden |first3=Safi K. |last4=Naisbett-Jones |first4=Lewis C. |last5=Laker |first5=Philippa R. |last6=Brown |first6=Antony M. |last7=Ramnarine |first7=Indar W. |last8=Walker |first8=Jeffrey |last9=Croft |first9=Darren P. |title=A Matador-like Predator Diversion Strategy Driven by Conspicuous Coloration in Guppies |journal=Current Biology |date=20 July 2020 |volume=30 |issue=14 |pages=2844–2851.e8 |doi=10.1016/j.cub.2020.05.017 |pmid=32531279 |s2cid=219572283 |language=en |issn=0960-9822|doi-access=free |bibcode=2020CBio...30E2844H |hdl=10871/120959 |hdl-access=free }}</ref><ref name="The Matador in Your Fish Tank">{{cite news |last1=Sima |first1=Richard |title=The Matador in Your Fish Tank |url=https://www.scientificamerican.com/article/the-matador-in-your-fish-tank/ |work=Scientific American |language=en}}</ref> Perhaps counterintuitively, this predator divertive behavior allows guppies to rapidly pivot out of the way as predators lunge where the guppies' head was; this "matador-like" anti-predator behavior was first described in guppies but may be found in other animal species with bright, attention-grabbing coloration located on vital organs, such as [[epaulette shark]]s.<ref name="The Matador in Your Fish Tank"/><ref name="A Matador-like Predator Diversion S"/>

===Parasites===
Guppies are also host to a range of parasites and one of these, ''[[Gyrodactylus turnbulli]]'', has been used as a model system for studying [[host-parasite interaction]]s.<ref name="Masud 2020">{{cite journal |last1=Masud |first1=Numair |last2=Hayes |first2=Laura |last3=Crivelli |first3=Davide |last4=Grigg |first4=Stephen |last5=Cable |first5=Jo |title=Noise pollution: acute noise exposure increases susceptibility to disease and chronic exposure reduces host survival |journal=Royal Society Open Science |date=2020 |volume=7 |issue=9 |page=200172 |doi=10.1098/rsos.200172|pmid=33047012 |pmc=7540788 |bibcode=2020RSOS....700172M |doi-access=free }}</ref> Recent work on this has shown that the interaction between exposure to chronic [[Noise pollution|anthropogenic noise]] and ''G. turnbulli'' can decrease guppy survival. While a short burst of underwater noise has positive effects on parasite densities on the host. Most likely resulting in negative [[Fitness (biology)|fitness]] effects for guppies.<ref name="Masud 2020"/>

===Feeding===
Wild guppies feed on algal remains, diatoms, invertebrates, zooplankton, detritus,<ref name="sta.uwi.edu">{{cite web|url=https://sta.uwi.edu/fst/lifesciences/sites/default/files/lifesciences/documents/ogatt/Poecilia_reticulata%20-%20Guppy.pdf|title=Online Guide to the Animals of Trinidad and Tobago [OGATT] - Guppy|website=Sta.uwi.edu|access-date=5 June 2023}}</ref> plant fragments, mineral particles, aquatic insect larvae, and other sources. Algal remains constitute the biggest proportion of wild guppy diet in most cases, but diets vary depending on the specific conditions of food availability in the habitat.<ref name="Dussault1981">{{cite journal |title=Food and feeding behavior of the guppy, ''Poecilia reticulata'' (Pisces: Poeciliidae) |journal=[[Canadian Journal of Zoology]] |first1=Gertrude V. |last1=Dussault |first2=Donald L. |last2=Kramer |volume=59 |issue=4 |pages=684–701 |year=1981 |doi=10.1139/z81-098}}</ref><ref name="Lawal2012">{{cite journal |title=Food and Feeding Habits of the Guppy, Poecilia reticulata, from Drainage Canal Systems in Lagos, Southwestern Nigeria |journal=West African Journal of Applied Ecology |first1=M. O. |last1=Lawal |first2=C. A. |last2=Edokpayi |first3=A. O. |last3=Osibona |volume=20 |issue=2 |pages=1–9 |year=2012 |url=http://www.ajol.info/index.php/wajae/article/view/86327 |archive-url=https://web.archive.org/web/20131203142213/http://www.ajol.info/index.php/wajae/article/view/86327 |archive-date=3 December 2013 |url-status=live}}</ref> For example, a study on wild Trinidad guppies showed that guppies collected from an [[oligotroph]]ic upstream region (upper Aripo River) mainly consumed invertebrates, while guppies from a [[eutrophication|eutrophic]] downstream region (lower [[Caura River (Trinidad and Tobago)|Tacarigua River]]) consumed mostly diatoms and mineral particles. Algae are less nutritious than invertebrates, and the guppies that feed mainly on algae have poor diets.<ref name="Magurran2005">{{cite book |title=Evolutionary Ecology: The Trinidadian Guppy |publisher=Oxford University Press |location=New York |first=Anne E. |last=Magurran |year=2005 |isbn=978-0-19-852786-2}}</ref>
[[File:Guppy Food - Daphnia Magna.png|thumb|Guppy food - ''Daphnia magna'']] Guppies have also been observed eating native fishes' eggs, occasionally expressing cannibalism, also eating its own young, when kept in laboratory conditions.<ref name="sta.uwi.edu"/>

Guppies' diet preference is not simply correlated to the abundance of a particular food. Laboratory experiments confirmed that guppies show 'diet switching' behavior, in which they feed disproportionately on the more abundant food when they are offered two food choices. The result shows that different groups of guppies have weak and variable food preference.<ref name="Murdoch1975">{{cite journal |title=Switching in Predatory Fish |journal=[[Ecology (journal)|Ecology]] |first1=William W. |last1=Murduch |first2=S. |last2=Avery |first3=Michael E. B. |last3=Smyth |volume=56 |issue=5 |pages=1094–1105 |year=1975 |doi=10.2307/1936149|jstor=1936149 |bibcode=1975Ecol...56.1094M }}</ref> Diet preference in guppies could be related to factors such as the presence of competitors. For example, the lower Tacarigua River has a larger variety of species and competition for invertebrate prey is higher; therefore, the proportion of invertebrates is small in the diets of those guppies.<ref name="Magurran2005" />

===Foraging===
Guppies often forage in groups because they can find food more easily. Shoaling guppies spend less time and energy on antipredatory behavior than solitary ones and spend more time on feeding. However, such behavior results in food that is found being shared with other members of the group. Studies also show when an evolutionary cost exists, guppies that tend to shoal are less aggressive and less competitive with regards to scarce resources.<ref name="Magurran1991">{{cite journal |title=Variation in schooling and aggression amongst guppy (Poecilia reticulata) populations in Trinidad |journal=Behaviour |first1=Anne E. |last1=Magurran |first2=Benoni H. |last2=Seghers |volume=118 |issue=3/4 |pages=214–234 |year=1991 |doi=10.1163/156853991X00292 |jstor=4534965|s2cid=84573662 |url=https://pdfs.semanticscholar.org/4d6c/930e9b64f988cebf4144204ba8aafc030cd7.pdf |archive-url=https://web.archive.org/web/20200213144742/https://pdfs.semanticscholar.org/4d6c/930e9b64f988cebf4144204ba8aafc030cd7.pdf  |archive-date=2020-02-13 }}</ref> Therefore, [[shoaling]] is preferred in high-predation regions, but not in low-predation regions. When guppies with a high tendency to shoal were isolated from high-predation regions and were relocated to predator-free environments, over time, they decreased their shoaling behavior, supporting the hypothesis that shoaling is less preferred in low-predation environments.<ref name="Magurran1992">{{cite journal |title=Behavioural Consequences of an Artificial Introduction of Guppies (''Poecilia reticulata'') in N. Trinidad: Evidence for the Evolution of Anti-Predator Behaviour in the Wild |journal=[[Proceedings of the Royal Society B]] |first1=Anne E. |last1=Magurran |first2=Benoni H. |last2=Seghers |first3=Gary R. |last3=Carvalho |first4=Paul W. |last4=Shaw |volume=248 |issue=1322 |pages=117–122 |year=1992 |doi=10.1098/rspb.1992.0050|s2cid=85844006 }}</ref>

==Reproduction==
[[File:Guppy riproduzione.ogv|thumb|Birth of guppy fry]]
[[File:Poecilia reticulata Fry DSC04357 nevit.jpg|thumb|A guppy [[Spawn (biology)#Fry|fry]] in an aquarium at one week of age]]

Guppies are highly prolific [[Live-bearing aquarium fish|livebearers]].<ref>{{cite encyclopedia |url=https://www.britannica.com/eb/article-9038553/guppy |title=Guppy |encyclopedia=Encyclopædia Britannica Online |year=2007 |access-date=7 May 2007 |archive-url=https://web.archive.org/web/20080513074309/https://www.britannica.com/eb/article-9038553/guppy |archive-date=13 May 2008 |url-status=live}}</ref> The [[gestation period]] of guppies varies considerably, ranging from 20 to 60 days at 25 to 27 C and depending on several environmental factors.<ref name="Evans 2000">{{cite journal |last1=Evans |first1=J. P. |last2=Magurran |first2=A. E. |title=Multiple benefits of multiple mating in guppies |journal=Proceedings of the National Academy of Sciences |date=2000 |volume=97 |issue=18 |pages=10074–10076 |doi=10.1073/pnas.180207297|pmid=10954750 |pmc=27698 |bibcode=2000PNAS...9710074E |doi-access=free }}</ref><ref name="Sato 2021">{{cite journal |last1=Sato |first1=Aya |last2=Aihara |first2=Ryu-ichi |last3=Karino |first3=Kenji |title=Male coloration affects female gestation period and timing of fertilization in the guppy (''Poecilia reticulata'') |journal=PLOS ONE|date=2021 |volume=16 |issue=12 |pages=e0261004 |doi=10.1371/journal.pone.0261004|pmid=34855912 |pmc=8639057 |bibcode=2021PLoSO..1661004S |doi-access=free }}</ref> Reproduction typically continues through the year, and the female becomes ready for conception again quickly after [[parturition]].<ref name="Magurran2005" /> Male guppies, like other members of the family [[Poeciliidae]], possess a modified tubular anal fin called the [[gonopodium]], located directly behind the [[ventral fin]]. The gonopodium has a channel-like structure through which bundles of [[spermatozoon|spermatozoa]], called spermatozeugmata, are transferred to females. In courted mating, where the female shows receptive behavior following the male's courtship display, the male briefly inserts the gonopodium into the female's genital pore for internal fertilization. However, in the case of sneaky mating where [[forced copulation|copulation is forced]], the male approaches the female and thrusts the gonopodium at the female's urogenital pore.<ref name="Reynolds1993">{{cite journal |title=Environmental conditions and male morphology determine alternative mating behavior in Trinidadian guppies |journal=[[Animal Behaviour (journal)|Animal Behaviour]] |first1=John D. |last1=Reynolds |first2=Mart R. |last2=Gross |first3=Mark J. |last3=Coombs |volume=45 |issue=1 |pages=145–152 |year=1993 |doi=10.1006/anbe.1993.1013|s2cid=53174560 |url=http://pdfs.semanticscholar.org/c77e/9fc3056160a533f54895e0da9829d54895a6.pdf |archive-url=https://web.archive.org/web/20190304140745/http://pdfs.semanticscholar.org/c77e/9fc3056160a533f54895e0da9829d54895a6.pdf  |archive-date=2019-03-04 }}</ref>

Once inseminated, female guppies can store sperm in their ovaries and gonoducts, which can continue to fertilize ova up to eight months.<ref name="Winge1937">{{cite journal |title=Succession of broods in ''Lebistes'' |journal=[[Nature (journal)|Nature]] |first=Ö. |last=Winge |volume=140 |issue=3541 |page=467 |year=1937 |doi=10.1038/140467b0|bibcode=1937Natur.140..467W |s2cid=4092610 |doi-access=free }}</ref> Because of the sperm-storage mechanism, males are capable of posthumous reproduction, meaning the female mate can give birth to the male's offspring long after the male's death, which contributes significantly to the reproductive dynamics of the wild guppy populations.<ref name="lopez-sepulcre 2013">{{cite journal |title=Beyond lifetime reproductive success: the posthumous reproductive dynamics of male Trinidadian guppies |journal=[[Proceedings of the Royal Society B]] |first1=Andrés |last1=López-Sepulcre |first2=Swanne P. |last2=Gordon |first3=Ian G. |last3=Paterson |first4=Paul |last4=Bentzen |first5=David N. |last5=Reznick |volume=280 |issue=1763 |year=2013 |doi=10.1098/rspb.2013.1116 |pmid=23740786 |pmc=3774245 |page=20131116}}</ref>

The guppy has been successfully hybridised with various species of molly (''[[Sailfin molly|Poecilia latipinna]]'' or [[poecilia velifera|''P. velifera'']]), e.g., male guppy and female molly. However, the hybrids are always male and appear to be infertile.<ref>{{cite journal |title=A Localized Melanoma in a Hybrid Fish Lebistes × Mollienesia |journal=[[Cancer Research (journal)|Cancer Research]] |first1=F. N. |last1=Ghadially |first2=M. |last2=Gordon |volume=17 |issue=6 |pages=597–599 |date=July 1957 |pmid=13446844}}</ref> The guppy has also been hybridised with the Endler's livebearer (''[[Poecilia wingei]]'') to produce fertile offspring, with the suggestion that, despite physical and behavioural differences, Endler's may represent a subspecies of ''Poecilia reticulata'' rather than a distinct species.<ref name="Griffitts1997">{{cite web |url=http://www.aquaworldaquarium.com/Articles/TonyGriffitts/Endlers_Livebearer.html |title=Endler's Livebearer |work=Aquaworld Aquarium |first=Tony |last=Griffitts |year=1997 |access-date=26 November 2013 |archive-url=https://web.archive.org/web/20131202221629/http://www.aquaworldaquarium.com/Articles/TonyGriffitts/Endlers_Livebearer.html |archive-date=2 December 2013 |url-status=live}}</ref><ref name="Griffitts2011">{{cite web |url=http://www.aquaworldaquarium.com/Articles/TonyGriffitts/Endlers_Livebearer_Its_A_Guppy.html |title=Endler's Livebearer: It's a Guppy! |work=Aquaworld Aquarium |first=Tony |last=Griffitts |year=2011 |access-date=26 November 2013 |archive-url=https://web.archive.org/web/20130724104814/http://aquaworldaquarium.com/Articles/TonyGriffitts/Endlers_Livebearer_Its_A_Guppy.html |archive-date=24 July 2013 |url-status=live}}</ref>

===Inbreeding depression===
Due to the extensive selective breeding of guppies for desirable traits such as greater size and colour, some strains of the fish have become less hardy than their wild counterparts. Immense inbreeding of guppies has been found to affect body size, fertility and susceptibility to diseases.<ref name="VanOosterhout2007">{{cite journal |title=The Guppy as a Conservation Model: Implications of Parasitism and Inbreeding for Reintroduction Success |journal=Conservation Biology |first1=Cock |last1=Van Oosterhout |first2=Alan M. |last2=Smith |first3=Bernd |last3=Hänfling |first4=Indar W. |last4=Ramnarine |first5=Ryan S. |last5=Mohammed |first6=Joanne |last6=Cable |display-authors=1 |volume=21 |issue=6 |pages=1573–1583 |date=December 2007 |doi=10.1111/j.1523-1739.2007.00809.x |jstor=4621001 |pmid=18173481|bibcode=2007ConBi..21.1573V |s2cid=23388119 }}</ref>

==In the aquarium==
[[File:Guppy-standards-grafik.svg|thumb|Guppy standards<br />
<br />
'''Large strains:'''<br />
'''A''' - Veil tail<br />
'''B''' - Triangle tail<br />
'''C''' - Fan tail<br />
'''D''' - Flag tail<br />
<br />
'''Sword strains:'''<br />
'''E''' - Double sword<br />
'''F''' - Upper sword<br />
'''G''' - Lower sword<br />
'''H''' - Lyre tail<br />
<br />
'''Short strains:'''<br />
'''I''' - Spade tail<br />
'''J''' - Spear tail<br />
'''K''' - Round tail<br />
'''L''' - Pin tail]]
Guppies prefer a [[hard water|hard-water]] [[aquarium]] with a temperature between {{convert|25.5|and|27.8|C|F|0}} and salt levels equivalent to one tablespoon per {{convert|5|USgal|L|abbr=on|order=flip}}.<ref name="Hargrove2006">{{cite book |title=Freshwater Aquariums for Dummies |publisher=Wiley |location=Hoboken |first1=Maddy |last1=Hargrove |first2=Mic |last2=Hargrove |edition=2nd |year=2006 |page=[https://archive.org/details/freshwateraquari00harg/page/99 99] |isbn=978-0-470-05103-0 |url-access=registration |url=https://archive.org/details/freshwateraquari00harg/page/99 }}</ref> They can withstand levels of [[salinity]] up to 150% that of normal [[seawater]],<ref>{{cite journal |title=Salinity tolerance of the guppy, ''Poecilia Reticulata'' Peters |journal=[[Journal of Fish Biology]] |first=J. |last=Chervinski |volume=24 |issue=4 |pages=449–452 |date=April 1984 |doi=10.1111/j.1095-8649.1984.tb04815.x|bibcode=1984JFBio..24..449C }}</ref> which has led to them being occasionally included in marine tropical community tanks, as well as in freshwater tropical tanks. Guppies are generally peaceful, though nipping behaviour is sometimes exhibited between male guppies or towards other top swimmers like members of the genus ''[[Xiphophorus]]'' (platies and swordtails), and occasionally other fish with prominent fins, such as [[Freshwater angelfish|angelfish]]. Guppies should not be kept as a single fish in an aquarium because both males and females show signs of [[shoaling and schooling|shoaling]], and are usually found in large groups in the wild.<ref>{{cite journal |url=https://fishfanfor.life/are-guppies-schooling-fish/ |title=Guppies are Schooling Fish |website=FishFanforLife |first=Swaraj |last=Nandedkar|date=30 September 2023 |doi=10.1007/BF00300143|s2cid=13158363 }}</ref> Its most famous characteristic is its propensity for breeding, and it can breed in both freshwater and marine aquaria.<ref name="Shikano1997">{{cite journal |title=Successful Propagation in Seawater of the Guppy ''Poecilia reticulata'' with Reference to High Salinity Tolerance at Birth |journal=Fisheries Science |first1=Takahito |last1=Shikano |first2=Yoshihisa |last2=Fujio |date=August 1997 |volume=63 |issue=4 |pages=573–575 |doi=10.2331/fishsci.63.573|doi-access=free |bibcode=1997FisSc..63..573S }}</ref>

Guppies prefer water temperatures around {{convert|22.2|-|26.1|C|F|0}} for reproduction. Pregnant female guppies have enlarged and darkened [[gravid spot]]s near their anal vents. Just before birth, the eyes of fry may be seen through the translucent skin in this area of the female's body.<ref>{{cite web |url=http://small-pets.lovetoknow.com/gestation-period-guppies |title=Gestation Period for Guppies |work=LoveToKnow.com |first=Melissa |last=Mayntz |access-date=25 November 2013 |archive-url=https://web.archive.org/web/20131203000757/http://small-pets.lovetoknow.com/gestation-period-guppies |archive-date=3 December 2013 |url-status=live}}</ref> When birth occurs, individual offspring are dropped in sequence, typically over a period of one to six hours. The female guppy has drops of two to 200 [[Spawn (biology)#Fry|fry]] at a time, though typically ranging between 30 and 60.<ref>{{cite web |url=http://small-pets.lovetoknow.com/pregnant-guppy-fish |title=Pregnant Guppy Fish |work=LoveToKnow.com |first=Dave |last=Donovan |access-date=25 November 2013 |archive-url=https://web.archive.org/web/20131202225400/http://small-pets.lovetoknow.com/pregnant-guppy-fish |archive-date=2 December 2013 |url-status=live}}</ref>

Well-fed adults do not often eat their own young, although sometimes safe zones are required for the fry. Specially designed livebearer birthing tanks, which can be suspended inside the aquarium, are available from aquatic retailers. These also serve to shield the pregnant female from further attention from the males, which is important because the males sometimes attack the females while they are giving birth.<ref>{{cite web |url=http://guppybreeding.net/guppy-breeding/breed-guppies-tips-you-need-to-know |title=Breed Guppies – Tips You Need to Know |work=Guppybreeding.net |date=20 April 2012 |access-date=6 December 2013 |archive-url=https://web.archive.org/web/20131224194503/http://guppybreeding.net/guppy-breeding/breed-guppies-tips-you-need-to-know/ |archive-date=24 December 2013  }}</ref> It also provides a separate area for the newborn young as protection from being eaten by their mother.<ref>{{cite web |url=http://guppyfishcare.com/guppy-fry-care |title=Guppy fry care: how to look after baby guppies |work=Guppyfishcare.com |date=12 October 2013 |access-date=6 December 2013 |archive-url=https://web.archive.org/web/20131022215116/http://guppyfishcare.com/guppy-fry-care/ |archive-date=22 October 2013 |url-status=live}}</ref> However, if a female is put in the breeder box too early, it may cause her to have a miscarriage. Well-planted tanks that offer barriers to adult guppies shelter the young quite well. [[Najas guadalupensis|Guppy grass]], [[Ceratopteris thalictroides|water sprite]], [[Hygrophila difformis|water wisteria]], [[Lemnoideae|duckweed]], [[Pistia|water lettuce]] and [[java moss]] are all good choices. A continuous supply of live food, such as ''[[Daphnia]]'' or [[brine shrimp]], keep adult fish full and may spare the fry when they are born.<ref>{{cite web |url=http://www.tropicalfauna.info/guppies.htm |title=Livebearers: Guppies |work=TropicalFauna.info |archive-url=https://web.archive.org/web/20131207071439/http://tropicalfauna.info/guppies.htm |archive-date=7 December 2013  |access-date=23 June 2012 }}</ref> Young fry take roughly three or four months to reach maturity. Feeding fry live foods, such as baby [[brine shrimp]], [[microworm]]s, [[infusoria]] and [[vinegar eel]]s, is recommended. Alternatives include finely ground flake food, egg yolk, and liquid fish food, though the particulates in these may be too large for the youngest fry to eat.<ref>{{cite web |url=http://www.fishchannel.com/freshwater-aquariums/fish-food/tiny-foods-for-small-fry.aspx |title=Tiny Foods For Small Fry |work=FishChannel.com |first=Fussell |last=Carroll |access-date=26 November 2013 |archive-url=https://web.archive.org/web/20131202232017/http://www.fishchannel.com/freshwater-aquariums/fish-food/tiny-foods-for-small-fry.aspx |archive-date=2 December 2013 |url-status=live}}</ref>

== Common diseases ==
Guppies are susceptible to various diseases, which may stem from bacterial, parasitic, or fungal infections. Maintaining a clean tank, a balanced diet, and regular monitoring can help in preventing these diseases.

=== ''Ichthyophthirius multifiliis'' (Ich) ===
''[[Ichthyophthirius multifiliis]]'', commonly known as ich, is a protozoan parasite that infects guppies and other freshwater fish. The infection is characterized by white cysts appearing on the skin, gills, and fins of the affected fish, giving a distinct white spot appearance which is often referred to as "white spot disease".<ref>{{Citation |last1=von Gersdorff Jorgensen |first1=Louise |title=Chapter 40 - Infection by Ichthyophthirius multifiliis |date=2022-01-01 |url=https://www.sciencedirect.com/science/article/pii/B9780128122112000408 |work=Aquaculture Pathophysiology |pages=493–503 |editor-last=Kibenge |editor-first=Frederick S. B. |access-date=2023-10-20 |publisher=Academic Press |isbn=978-0-12-812211-2 |last2=Puspasari |first2=Khumaira |last3=Insariani |editor2-last=Baldisserotto |editor2-first=Bernardo |editor3-last=Chong |editor3-first=Roger Sie-Maen}}</ref>

The life cycle of ''Ichthyophthirius multifiliis'' involves three stages: the trophont stage, the tomont stage, and the theront stage.

=== Fin rot ===
[[Fin rot]] is primarily caused by bacterial infections, although fungal infections can also be a culprit. The condition manifests through the progressive decay or fraying of the fins, often accompanied by discoloration, usually turning the edges of the fins white, black, or red. The primary causative agents of fin rot are gram-negative bacteria such as ''[[Pseudomonas fluorescens]]'' and ''[[Aeromonas hydrophila]]''.<ref>{{Cite journal |last1=Caldwell |first1=Melba C. |last2=Caldwell |first2=David K. |last3=B. C. Townsend |first3=Jr |date=2015-03-30 |title=IAAAM Archive |url=http://www.vin.com/doc/?id=6696240 |website=VIN.com}}</ref> Poor water quality, overcrowding, and stress are significant contributors to the onset and progression of the disease, as they create an environment conducive for bacterial growth and can compromise the fish's immune system.<ref>{{Cite web |date=2023-09-24 |title=Guppy Fin Rot: Causes, Symptoms, and Treatments |url=https://oakharts.com/guides/fish-care/guppy/guppy-fin-rot-causes-symptoms-and-treatments/ |access-date=2023-10-20 |language=en-US}}</ref>

=== Columnaris ===
[[Columnaris]], also known as cotton mouth disease or cotton wool disease, is a common bacterial infection in guppies and other freshwater fish, caused by the bacterium ''[[Flavobacterium columnare]]''. This bacterium thrives in warm, freshwater environments. Treatment for columnaris should commence promptly to prevent severe mortality. Common treatment measures include: improving water quality, antibacterial medications such as [[Kanamycin A|kanamycin]], [[erythromycin]], or [[oxytetracycline]], and in extreme cases, antibiotic injections.<ref>{{Cite web |last=Medicine |first=Center for Veterinary |date=2020-10-27 |title=Everything Aquatic - 610530 - 10/06/2020 |url=https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/everything-aquatic-610530-10062020 |access-date=2023-10-20 |website=Center for Veterinary Medicine |language=en}}</ref><ref>{{Cite journal |last1=Declercq |first1=Annelies Maria |last2=Haesebrouck |first2=Freddy |last3=Van den Broeck |first3=Wim |last4=Bossier |first4=Peter |last5=Decostere |first5=Annemie |date=2013-04-24 |title=Columnaris disease in fish: a review with emphasis on bacterium-host interactions |journal=Veterinary Research |volume=44 |issue=1 |page=27 |doi=10.1186/1297-9716-44-27 |issn=1297-9716 |doi-access=free |pmid=23617544 |pmc=3648355 }}</ref>

=== Velvet disease ===
[[Velvet (fish disease)|Velvet]], also known as gold dust disease, is a prevalent ailment caused by the [[dinoflagellate]] parasites of the genus ''[[Oodinium]]''.<ref>{{Cite book |last=Noga |first=Edward J. |url=https://onlinelibrary.wiley.com/doi/book/10.1002/9781118786758 |title=Fish Disease: Diagnosis and Treatment |date=2010-06-18 |publisher=Wiley |isbn=978-0-8138-0697-6 |edition=1 |language=en |doi=10.1002/9781118786758}}</ref> When these parasites attach to a fish's skin, gills, and eyes, they trigger a range of symptoms. Notable symptoms include a fine gold or rust-colored dust appearing on the fish's body, clamped fins, scratching against objects, rapid gill movement due to irritation, decreased feeding, lethargy, and, in advanced stages, respiratory distress.

=== Swim bladder disease ===
[[Swim bladder disease]] is a common condition which impairs their ability to maintain buoyancy. This condition is associated with the swim bladder, a gas-filled organ that aids fish in remaining buoyant at varying water depths. The symptoms of swim bladder disease are quite distinctive and include difficulty in maintaining buoyancy which causes the fish to either float to the top or sink to the bottom, abnormal swimming patterns such as swimming on the side or upside down, and a bloated appearance or a visibly enlarged belly.

Several factors can contribute to the onset of swim bladder disease. Overfeeding is a common cause, leading to constipation which may press against the swim bladder. Bacterial or viral infections affecting the swim bladder can also trigger this condition.<ref>{{Cite book |url=https://www.taylorfrancis.com/books/9781498727877 |title=Fish Diseases and Medicine |date=2019-04-02 |publisher=CRC Press |isbn=978-0-429-19525-9 |editor-last=Smith |editor-first=Stephen A. |edition=1 |location=Boca Raton, Florida : CRC Press, [2019] |language=en |doi=10.1201/9780429195259|s2cid=232970157 }}</ref> Physical injury or congenital deformities of the [[swim bladder]] are other potential causes.{{clear}}

==References==
{{Reflist}}

==Further reading==
* {{cite book |title=Sex, Color, and Mate Choice in Guppies |publisher=Princeton University Press |location=Princeton, NJ |first=Anne E |last=Houde |year=1997 |page=227 |isbn=978-0-691-02789-0}}

==External links==
{{Commons category|Poecilia reticulata}}
{{Wikispecies|Poecilia reticulata}}
* {{FishBase |genus=Poecilia |species=reticulata |month=April |year=2004}}

{{Taxonbar|from=Q178202}}
{{Authority control}}

[[Category:Poecilia]]
[[Category:Ovoviviparous fish]]
[[Category:Fish of the Caribbean]]
[[Category:Fauna of Antigua and Barbuda]]
[[Category:Fauna of Barbados]]
[[Category:Euryhaline fish of Brazil]]
[[Category:Fish of Guyana]]
[[Category:Fish of Trinidad and Tobago]]
[[Category:Freshwater fish of Venezuela]]
[[Category:Fish described in 1859]]
[[Category:Taxa named by Wilhelm Peters]]
[[Category:Articles containing video clips]]