Ecology and life history of an Amazon floodplain cichlid: the discus fish Symphysodon (Perciformes: Cichlidae)
William G. R. Crampton
Department of Biology, University of Central Florida, P.O. Box 162368. Orlando, FL, 32816, U.S.A
Er en feltstudie rapport om Discus i Amazonas som det også har stor verdi å lese igjennom.
ABSTRACT
The discus fishes of the genus Symphysodon are popular ornamental cichlids that occur in floodplain lakes and flooded forests of the lowland Amazon Basin. These habitats are characterized by extreme seasonal fluctuations in the availability of food, shelter and dissolved oxygen, and also the densities of predators and parasites. Most aspects of discus biology are influenced by these fluctuating conditions. This paper reports an autoecological study of the western Amazonian discus S. haraldi (until recently classified as S. aequifasciatus).
This species feeds predominantly on algal periphyton, fine organic detritus, plant matter, and small aquatic invertebrates. At high water it forages alone or in small groups in flooded forests. At low water it forms large aggregations in fallen tree crowns along lake margins. Breeding occurs at the beginning of the flood season, ensuring that the progeny are well grown before the next low water period. Symphysodon haraldi is an iteroparous partial spawner, reaches reproductive maturity within a year, and undertakes parental care of its eggs and larvae. The timing of spawning events, and/or the rate of brood survival, may be influenced by fluctuations in the flood level, resulting in a non-unimodal distribution of size classes for the subsequent 1+ cohort.
Les nøye den rødfarget teksten for se hva Discus artene spiser i naturen. Hvorfor skal vi i akvarium presse en for det meste vegetar spisende fisk til å spise kjøtt fra varmblodsdyr? Dette er ikke logisk. Jeg spørr videre hvorfor gjør så mange akvarister dette? Hvorfor utvikles det kommersielt tørrfor bassert på hjerterkjøtt fra varmblodsdyr til Discus? Jeg tror det er på tid at de som er så store tilhengere av hjertekjøtt fra varmblodsdyr som for til Discus forteller om dette og de fordeler dette foret gir til fisk og akvarist. Er de helsemessige sidene hos fisken er undersøkt etter slik foring?
