Dwarf gourami

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Dwarf gourami
Dwarf gourami (Trichogaster lalius) ♂

Dwarf gourami ( Trichogaster lalius ) ♂

Systematics
Order : Climbing fish species (Anabantiformes)
Subordination : Labyrinth fish (Anabantoidei)
Family : Osphronemidae
Subfamily : Threadfish (Trichogastrinae)
Genre : Trichogaster
Type : Dwarf gourami
Scientific name
Trichogaster lalius
( Hamilton , 1822)

The dwarf gourami ( Trichogaster lalius , Syn .: Colisa lalia ) is a freshwater fish from the suborder of the labyrinth fish (Anabantoidei) and the most widespread representative of the " western gouramis " in South Asia .

features

Dwarf threadfish rarely reach a total length of more than five centimeters. From their sister species, the striped threadfish ( Trichogaster fasciata ) and the thick-lipped threadfish ( Trichogaster labiosa ), they differ significantly in their smaller size and their squat and high-backed physique. Sexually mature females show a silver-gray basic color, on which up to 14 weakly pronounced oblique and bluish shimmering vertical bands extend from the end of the gill to the base of the caudal fin . When excited, the penultimate vertical band forms a round blue spot in the middle. The fins of the females are colorless, the dorsal and anal fins are only slightly reddish. In contrast, adult males have a strong red base color, which is usually overlaid by twelve pronounced light to turquoise blue shiny vertical stripes. Throat and chest are also colored bright blue; during courtship the throat can show a strong dark blue. The unpaired fins are spotted light blue and red, with blue predominating in the hard-nosed part of the dorsal fin and the hard-nosed part of the anal fin being lined with turquoise blue. The eyes of the males are bright red. The anal fin is rounded in both sexes. In males, the dorsal fin may taper off slightly pointed or rounded.

Fins formula : dorsal XV – XVII / 7–10, anal XVII – XVIII / 13–17.

Males and smaller females
blue cultivar

ecology

Presumably, the original habitat of the dwarf gourami extends over the lowlands of the great Indian rivers Brahmaputra and Ganges . As a small, but important food fish due to its abundance, the species was spread over almost all of northern India and beyond. Trichogaster lalius is found today in India , Pakistan , Nepal , Bangladesh and Myanmar . In the dry season , dwarf gourami socialize and migrate through deeper water zones. During the rainy season they move to the nutrient-rich bank and floodplain zones, where the males begin the breeding season by defending nesting areas. Dwarf threadfish feed on insect larvae , molluscs and also on flying insects.

Reproduction

Male dwarf gourmets establish breeding grounds in habitats overgrown with water or inundated land plants, in which they build a compact foam nest from saliva-filled air bubbles and parts of plants, clearly protruding above the water surface . For genus-typical reproductive behavior see under thread fish . Even with this species, the brood care carried out by the male alone ends after five to six days with the swarming of the young fish.

Systematics

Francis Hamilton described the dwarf gourami in 1822 as Trichopodus lalius from the "Gangetic provinces, India". There is no holotype , but a brief species diagnosis and a drawing that leave no doubt as to the uniqueness of the species. Other synonyms are Trichopodus cotra Hamilton 1822, Colisa unicolor Cuvier in Cuvier & Valenciennes 1831 and Polyacanthus lalius (Hamilton 1822). The scientific species name is derived from the Indian dialect in Assam , where the dwarf gourami is called "Lal kholisha" after Day . For generic affiliation see under thread fish and the discussion on honey gourami .

Importance to humans

Dried or as a component of fishmeal , dwarf gourmets are an important factor in human nutrition due to their frequent occurrence in their home. Dwarf gourmets have long been a popular model in behavioral research . In addition, dwarf gouramis are under aquarium friends popular since its first introduction to Europe (1903 by animal dealers Stüve to Hamburg) and common aquarium fish that regularly come as standard in the aquarium trade. Several cultivated forms have emerged under the names "blue dwarf gourami", "neon dwarf gourami", "red dwarf gourami" and "rainbow gourami", which, as a typical domestication feature, are significantly larger and stronger than the natural species. There is also a veil-fin cultivated form.

literature

  • Michael Kokoscha: Labyrinth Fish . Ulmer Verlag, Stuttgart 1998, ISBN 3-8001-7431-6 .
  • Jörg Vierke: Labyrinth fish . Franckh'sche Verlagshandlung W. Keller & Co., Stuttgart 1986, ISBN 3-440-05594-9 .

swell

  • F. Hamilton: An account of the fishes found in the river Ganges and its branches . Edinburgh / London 1822, pp. 1–39.
  • AGK Menon: Check list - fresh water fishes of India . (= Records of the Zoological Survey of India. Occasional Paper No. 175). Miscellaneous Publication, 1999, ISBN 81-85874-15-8 .
  • MR Mirza: Checklist of freshwater fishes of Pakistan. In: Pakistan Journal of Zoology. Suppl. Ser. 3, 2003, pp. 1-30.
  • AKA Rahman: Freshwater Fishes of Bangladesh . The Zoological Society of Bangladesh, 1989, OCLC 1123521297 .
  • PK Talwar, AG Jhingran: Inland fishes of India and adjacent countries. 2 volumes. Oxford & IBH Publishing Co., New Delhi / Bombay / Calcutta 1991, ISBN 81-204-0639-7 .
  • A. Wakiyama, H. Kohno, Y. Taki: Genetic relationships of anabantoid fishes. In: Journal of the Tokyo University of Fisheries. Volume 83, No. 1-2, 1997, pp. 93-102

Web links

Commons : dwarf gourami  - album with pictures, videos and audio files