Invertebrates can make up 38% of the stomach content in wild S. primarily feed on algae, other plant material, and detritus ( periphyton), but also eat small invertebrates. on egg yolk, brine shrimp, or other replacement foods). 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. Research 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. Although rare in fish, more than 30 species of cichlids are known to feed their young with skin secretion to various extent, including Pseudetroplus and Uaru species. In the last 2 weeks, they swim away, resulting in the young being gradually "weaned off" and starting to fend for themselves. During the first two weeks, the parents stay near their young allowing them to feed easily. Additionally, adult discus produce a secretion ("discus milk") through their skin, on which the larvae live during their first 4 weeks. As with most cichlids, brood care is highly developed with both the parents caring for the young. When breeding, the pair moves away from the group, possibly to reduce the risk of cannibalism of the young. are highly social, typically occurring in groups that may number many dozens of individuals, which is unique among cichlids of the Americas. Based on RAPD sequences, the captive variants popularly known as turquoise, pigeon, ghost, cobalt and solid red are derived from wild green, blue and brown discus (not Heckel discus). In addition to the wild discus, several captive variants achieved by selective breeding exist. Some hybridisation occurs (or has occurred) between the brown discus and neighbouring forms, but overall they maintain their separate evolutionary trajectories. aequifasciatus, has been adopted by the Catalog of Fishes. This taxonomy with four described valid species, S. The Xingu group currently lacks a scientific name, but it is possible that the correct name for the blue is S. aequifasciatus East Amazon downriver from Meeting of Waters), Xingu group ( S. 1 central Amazon from Purus arch to the Meeting of Waters), brown ( S. tarzoo West Amazon drainages upriver from the Púrus Arch, blue ( S. discus Rio Negro, upper Uatumã, Nhamundá, Trombetas and Abacaxis), green ( S. Their assigning of scientific names to species differed to some extent from that used by earlier authors: Heckel ( S. They recognized them as evolutionarily significant units and species. Two captive variants (orange and solid turquoise)Ī molecular study in 2011 found five main groups, which generally matched previously recognized phenotypes. aequifasciatus remains to be determined if valid it is widespread but it might just be a color morph. discus, meanwhile, seem to hybridise frequently in the wild or have diverged recently, as they lack mitochondrial DNA lineage sorting but differ in color pattern and have dissimilar chromosomal translocation patterns. tarzoo was described in 1959 and applies to the red-spotted western population. Other species and subspecies have been proposed, but morphometric data (unlike in Pterophyllum, the freshwater angelfish) varies as much between individuals from one location as across the whole range of all discus fish species. haraldi, currently considered a synonym of S. tarzoo was not described in accordance with ICZN rules and thus should be considered invalid and replaced with S. A review published in 2007 largely came to the same result, but differed in nomenclature, as the species called S. tarzoo, based on a taxonomic review published in 2006. Discus are fish from the genus Symphysodon, which currently includes the species S.
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