Editing Livebearers

{{Short description|Fish that give birth to free swimming offspring}}
[[Image:Poecilia reticulata Fry DSC04357 nevit.jpg|thumb|[[Guppy]] fry 1 week old]]
'''Livebearers''' are [[fish]] that retain their eggs inside the body and give birth to live, free-swimming young. They are especially prized by aquarium owners. Among aquarium fish, livebearers are nearly all members of the family [[Poeciliidae]] and include: [[guppy]], [[fancy molly|molly]], [[platies|platy]], [[Poecilia wingei|endler’s]] and [[swordtail]]s.<ref name="Alderton2012">{{cite book|url=https://books.google.com/books?id=BKIKBgAAQBAJ|title=Livebearers: Understanding Guppies, Mollies, Swordtails and Others|author=David Alderton|date=15 May 2012|publisher=CompanionHouse Books|isbn=978-1-62008-006-1}}</ref>

The advantages of livebearing to the aquarist are that the newborn [[juvenile fish]] are larger than newly-hatched fry, have a lower chance of mortality and are easier to care for. Unusual livebearers include [[seahorse]]s and [[pipefish]], where the males care for the young, and certain [[cichlid]]s that are [[mouthbrooder]]s, with the parent incubating the eggs in the [[mouth|buccal cavity]].

==Common aquarium livebearers==
<!-- These aren't common and should not be listed under common! And not all sharks and rays are livebearers. The [[coelacanth]], [[Embiotocidae| surf perches]], and many types of [[shark| sharks]] and [[Batoidea|rays]] are all livebearing fish, aquarists do not usually keep these.-->Species of interest to aquarists are almost always members of the family [[Poeciliidae]], most commonly [[guppies]], [[fancy molly|mollies]], [[Platy (fish)|platies]], [[Xiphophorus|swordtails]], [[Poecilia wingei|Endler's livebearer]], and [[mosquitofish]]. Most of these are [[ovoviviparous]], with the developing embryos receiving no nourishment from the parent fish, but a few are [[viviparous]], receiving food from the maternal blood supply.<ref>{{Cite web |title=Livebearing Aquarium Fish—Habitat, Diet, and Breeding |url=https://www.thesprucepets.com/livebearing-aquarium-fish-1378599?utm_source=chatgpt.com |access-date=2025-05-15 |website=The Spruce Pets |language=en}}</ref> 

Because the newborn fish are large compared to the fry of [[oviparous]] fish, <!-- Added clarification to oviparous.-->which are those that lay eggs, newborn fish of livebearers are easier to feed than the fry of egg-laying species, such as characins and cichlids. This makes them much easier to raise, and for this reason, aquarists often recommend them for beginning fish breeder hobbyists.<!-- Minor language changes and clarifications added.--> The larger livebearer fry makes them far less vulnerable to predation, as the parents often eat fry if hungry. With the sufficient cover in the way of plants or porous objects, they can sometimes mature in a community tank.<ref>{{Cite web |title=Livebearers: Raise Guppies, Mollies, Platies & Swordtails in your Aquarium |url=https://www.liveaquaria.com/article/257/?aid=257 |access-date=2022-09-08 |website=www.liveaquaria.com}}</ref>

==Ovoviviparous and viviparous fish compared==
Most of the Poeciliidae are [[ovoviviparous]], that is, while the eggs are retained inside the body of the female for protection, the eggs are essentially independent of the mother and she does not provide them with any nutrients. In contrast, fish such as splitfins and halfbeaks are [[viviparous]], with the eggs receiving food from the maternal blood supply through structures analogous to the [[placenta]] of [[placental mammals]].<ref>{{Cite book |last=Blackburn |first=D.G. |url=https://www.worldcat.org/oclc/1045069010 |title=Viviparity and oviparity: evolution and reproductive strategies |date=2018 |work=Encyclopedia of reproduction. Volume 1, Male reproduction |others=Michael K. Skinner |isbn=978-0-12-815145-7 |editor-last=Jégou |edition=2nd |location=Oxford |pages=994–1003 |oclc=1045069010}}</ref>

==Aberrant livebearers and mouthbrooders==
[[Seahorse]]s and [[pipefish]] can be defined as livebearers, although in these cases the males incubate the eggs rather than the females. In many cases, the eggs are dependent on the male for oxygen and nutrition so these fish can be further defined as viviparous livebearers. <ref name="Cole2010">{{cite book |last=Cole |first=Kathleen S. |title=Reproduction and Sexuality in Marine Fishes: Patterns and Processes |publisher=University of California Press |location=Berkeley |date=2010 |pages=129–150 |isbn=978-0-520-26433-5}}</ref>

Many [[cichlid]]s are [[mouthbrooder]]s, with the female (or more rarely the male) incubating the eggs in the mouth. Compared with other cichlids, these species produce fewer but bigger eggs, and when they emerge, the fry is better developed and has higher survivability. Because the eggs are protected from the environment but do not absorb nutrients from the parent, this condition is [[Convergent evolution|analogous]] to, though not [[Homology (biology)|identical]] with, ovoviviparity.<ref name="Keenleyside1991">{{cite book |last=Keenleyside |first=Miles H.A. |title=Cichlid Fishes: Behaviour, Ecology and Evolution |publisher=Chapman & Hall |location=London |date=1991 |pages=191–210 |isbn=978-0-412-32200-6}}</ref>

==Livebearer fish gallery==
<gallery heights="100px" mode="packed">
Image:Guppy-male.jpg
Image:Poecilia latipinna.jpg
Image:Poecilia reticulata 01.jpg
Image:Xiphophorus helleri 03.jpg
Image:Dermogenys sumatrana 02.jpg
</gallery>

==References==
{{Reflist}}

==External links==
* [http://livebearers.org American Livebearer Association]
* [http://www.britishlivebearerassociation.co.uk/ British Livebearer Association]
* [https://web.archive.org/web/20060303224019/http://homepage.mac.com/nmonks/aquaria/halfbeaks.html Keeping & Breeding Halfbeaks] Includes growth rate chart and pictures of newborn fish.
* [http://thefishdoctor.co.uk/livebearer/maintaining-a-healthy-livebearer-aquarium/ How to Keep Livebearers]

[[Category:Aquariums]]
[[Category:Ovoviviparous fish]]
[[Category:Viviparous fish]]
[[Category:Live-bearing fish]]