Mosaic gourami
| Mosaic gourami | ||||||||||||
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Mosaic Gourami, male |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Trichopodus leerii | ||||||||||||
| ( Bleeker , 1852) |
The mosaic gourami ( Trichopodus leerii , syn .: Trichogaster leerii ) is a labyrinth fish widespread in Southeast Asia . It is the most colorful representative of the " Eastern threadfish ".
features
With a total length of up to twelve centimeters, the mosaic threadfish is the smallest of the five species of "Eastern threadfish". Females have a silver-gray throat and abdominal region, a short dorsal fin and rounded dorsal and anal fins . The scales are silvery with a brown border. The thickness of this border increases from the belly line towards the back, so that a color gradient from light (belly) to dark (back) is achieved. This honeycomb-like pattern, which resembles a mother-of-pearl shiny mosaic, is continued in the unpaired fins. An irregular dark brown band runs from the tip of the snout to the base of the caudal fin . The male also has this basic coloration. But the scales can reflect between silvery and a light blue. Its throat, the pelvic fins that have been transformed into the eponymous threads , the belly itself and the hard-radiating part of the anal fin are intensely red-orange in color. The dorsal fin is longer than that of the female and can reach the beginning of the caudal fin. In addition, the soft rays of the unpaired fins grow thread-like, making the fin surface appear larger. The pattern continues in these fin extensions.
Fin formula : dorsal V-VII / 8-10, anal XII-XIV / 25-30.
ecology
Since all threadfish are relatively important edible fish in Southeast Asia , they were already spread by humans before their scientific discovery. Their original occurrence areas can therefore no longer be determined. This also applies to the mosaic gourami, which is widespread today on the large Sunda Islands of Borneo and Sumatra and in the southern part of the Malay Peninsula . There he inhabits the flat zones of standing and slowly flowing, clear, soft and slightly acidic water bodies that are either shaded by bank vegetation or densely weed. In contrast to its sister species, the mosaic gourami is rarely found in cultivated waters (rice fields and irrigation systems). Mosaic gourami feed on molluscs , small crustaceans , insects and their larvae.
Reproduction
Reproductive males defend a breeding area, in the center of which they build a foam nest consisting exclusively of air bubbles coated with a secretion formed in the mouth. The foam nest only extends a little above the water surface, but because the male continues to build on it during brood care, it can occupy a large area (30 cm² and above). With a successfully courted female ready to spawn, eggs are laid and fertilized according to a ritualized behavior from being wrapped around under the foam nest. The light eggs float to the surface of the water and are picked up by the male with his mouth and brought together at a point under the nest. The egg development takes one to one and a half days, then the larvae, equipped with a large yolk supply, hatch. When they leave the nest after two to four days, the brood care carried out exclusively by males ends. Two observations on reproductive behavior distinguish mosaic gourmets from all other gourmands. Jörg Vierke and Robert Donoso-Büchner agree that some males ingest sand with their mouths and spit it into their foam nest. The sand trickles to the ground and forms a small mound under the foam nest. The biologist Dieter Vogt reports that mosaic threadfish are bred in aquarium fish farms in Malaysia in complete darkness. The fish spawn in large tubs with a low water level, placed in the banana leaves and completely covered with dark foil.
Importance to humans
Live and freshly dead mosaic gourami are part of the daily offer at the fish markets in their homeland. Mosaic threadfish have been popular and widespread aquarium fish since they were first imported into Europe (1933 by the Härtel breeding company in Dresden) . They are regularly offered in pet shops. Only offspring from Southeast Asia ( Thailand , Malaysia, Singapore ) are marketed . Occasionally very large, particularly colorful specimens are traded. These fish are treated with growth hormones and are not fertile .
Systematics
The Dutch doctor and naturalist Pieter Bleeker described the mosaic gourami in 1852 as Trichopus leerii from Palembang on the Indonesian island of Sumatra. The holotype is lost. The spelling "Leeri", with just an i, is incorrect because, due to a decision by the Nomenclature Commission, only the endings of species names with a double i, which were common in original descriptions in the 19th century, are valid. The generic name indicates the thread-like ventral fins ("Thrix" = "hair", "Pous" = "foot or fin"). Bleeker named the species in honor of his friend, the Dutch doctor JM Leer. Together with the moonlight gourami ( Trichopodus microlepis ), the dotted gourami ( Trichopodus trichopterus ) and the blade gourami ( Trichopodus pectoralis ), the pearl gourami forms the group of the "Eastern thread fish".
literature
- Michael Kokoscha: Labyrinth Fish . Verlag Eugen Ulmer, 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
- Bleeker, P. (1852): Diagnostische Beschrijvingen van nieuwe of weinig bekende vischsoorten van Sumatra . Tiental I - IV. Natuurkundig Tijdschrift voor Nederlandsch Indië v. 3: 569-608.
- Kottelat, M., AJ Whitten, SN Kartikasari & S. Wirjoatmodjo (1993): Freshwater fishes of Western Indonesia and Sulawesi . Periplus Editions, Hong Kong. i-xxxviii + 1-259, Pls. 1-84.
- Kottelat, M. & E. Widjanarti (2005): The fishes of Danau Sentarum National Park and the Kapuas Lakes area, Kalimantan Barat, Indonesia . The Raffles Bulletin of Zoology Suppl. No. 13: 139-173.
- Roberts, TR (1989): The freshwater fishes of western Borneo (Kalimantan Barat, Indonesia) . Memoirs of the California Academy of Sciences No. 14: i-xii + 1-210.
Web links
- Trichopodus leerii on Fishbase.org (English)
- Trichopodus leerii in the "Catalog of Fishes"
- Trichopodus leerii inthe IUCN 2013 Red List of Threatened Species . Listed by: Vidthayanon, C., 2011. Retrieved December 10, 2013.