Editing Discus (fish) (section)

==Behavior==
[[File:Discus fish with young.jpg|thumb|Discus with two of its young nearby]]
''Symphysodon'' spp. are highly social, typically occurring in groups that may number many dozens of individuals, which is unique among cichlids of the Americas.<ref name=Campton2008/> When breeding, the pair moves away from the group, possibly to reduce the risk of [[Cannibalism (zoology)|cannibalism]] of the young.<ref name=Campton2008/> As with most cichlids, brood care is highly developed with both the parents caring for the young.<ref name="freshwatercentral">{{Cite web |last=freshwatercentral |date=2019-11-26 |title=The Complete Discus Fish Care Guide |url=https://freshwatercentral.com/discus-fish |access-date=2019-11-26 |website=Freshwater Central |language=en-US |archive-date=2022-06-30 |archive-url=https://web.archive.org/web/20220630095536/https://www.freshwatercentral.com/discus-fish |url-status=dead }}</ref> Additionally, adult discus produce a [[secretion]] ("discus milk")<ref>{{cite book |doi=10.1016/S1546-5098(08)60098-9 |chapter=Prolactin (Fish Prolactin or Paralactin) and Growth Hormone |title=The Endocrine System |series=Fish Physiology |date=1969 |last1=Ball |first1=J.N. |volume=2 |pages=207–240 |isbn=978-0-12-350402-9 |quote-page=219 |quote=A special case is the discus fish, a cichlid Symphysodon discus, in which the skin of brooding fish hypertrophies and secretes mucus ('discus milk') which is eaten by the fry }}</ref> through their skin, on which the [[larva]]e live during their first 4 weeks.<ref name="Buckley">{{Cite journal |last1=Buckley |first1=J. |last2=Maunder |first2=R. J. |last3=Foey |first3=A. |last4=Pearce |first4=J. |last5=Val |first5=A. L. |last6=Sloman |first6=K. A. |year=2010 |title=Biparental mucus feeding: a unique example of parental care in an Amazonian cichlid |journal=J. Exp. Biol. |volume=213 |issue=22 |pages=3787–3795 |doi=10.1242/jeb.042929 |pmid=21037057 |doi-access=free|bibcode=2010JExpB.213.3787B |hdl=10026.1/12620 |hdl-access=free }}</ref> During the first two weeks, the parents stay near their young allowing them to feed easily. In the last 2 weeks, they swim away, resulting in the young being gradually "weaned off" and starting to fend for themselves.<ref name=Buckley/> Although rare in fish, more than 30 species of cichlids are known to feed their young with skin secretion to various extent,<ref name=Buckley/> including ''[[Pseudetroplus]]'' and ''[[Uaru]]'' species.<ref>{{Cite web |last=Leibel |first=W. |year=2010 |title=Cichlids of the Americas - Mouthbrooders |url=http://www.fishchannel.com/freshwater-aquariums/fish-breeding/mouthbrooders.aspx |access-date=22 January 2017 |publisher=FishChanel}}</ref> Sexual maturity is reached in a year.<ref name=Campton2008/>

Research <ref name="Sylvain">{{Cite journal |last1=Sylvain |first1=François-Étienne |last2=Derome |first2=Nicolas |year=2017 |title=Vertically and horizontally transmitted microbial symbionts shape the gut microbiota ontogenesis of a skin-mucus feeding discus fish progeny |journal=Scientific Reports |volume=7 |issue=1 |page=5263 |bibcode=2017NatSR...7.5263S |doi=10.1038/s41598-017-05662-w |pmc=5507859 |pmid=28701764}}</ref> has shown that, through this unique parental care behaviour (discus parents feeding their progeny with skin mucus), discus fish parents transmit key microorganisms to their fry. This parent-to-offspring transmission of important microorganisms might explain the high survival rate of discus fry raised with their parents, compared to the low survival rate of progeny raised artificially by fish breeders (e.g. on egg yolk, brine shrimp, or other replacement foods).<ref name=Sylvain/>

''Symphysodon'' spp. primarily feed on [[algae]], other plant material, and [[detritus]] ([[periphyton]]), but also eat small [[invertebrates]]. Invertebrates can make up 38% of the stomach content in wild ''S. aequifasciatus'' during the high-water season, but this decreases during the low-water season, and year-round it is generally lower in the other species.<ref name=Campton2008/> Unlike more predatory cichlids, ''Symphysodon'' spp. have relatively long [[intestine]]s typical of a [[herbivore]] or [[omnivore]].<ref name=Campton2008/>