Black muzzle
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Black-mouthed Parrot ( Poecilia sphenops ) |
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| Poecilia sphenops | ||||||||||||
| Valenciennes , 1846 |
The poecilia sphenops ( Poecilia sphenops , Greek sphenops "pointed head") is an in South and Central America occurring livebearers of the genus Poecilia . There are different cultivated forms of the species. Under the name Black Molly (derived from the name of the subgenus, Mollienesia ), a black cultivated form has found widespread use as an aquarium fish .
distribution and habitat
The black-and- white fish lives in fresh and brackish water from Texas to Colombia and Venezuela . In Europe, like other Poecilia species, the black-mouthed black fish can occasionally be found in artificially warmed waters, for example in the vicinity of power stations. These populations are due to stocking by former keepers. The species is not yet considered an established neozoon .
Appearance
The elongated body reaches a total length of four to six centimeters in male black muzzle. The females are significantly larger with six to ten centimeters and appear overall fuller with significantly more body mass. Their weight is on average 100 grams. The males have an anal fin that has been converted into a mating organ ( gonopodium ). Life expectancy in captivity can be up to five years. The head is pointed. The species forms a multitude of local forms with different colors, so a general description of the drawing is only possible to a very limited extent. The basic color is often blue-gray to brown-olive. Several rows of orange-colored dots and blue-green glittering spots run across the sides of the body. The pectoral and pelvic fins are usually colorless, the anal fin often orange. Often black spots can be found on the dorsal fin and often an orange-colored border with a black border.
- Dorsal 8–9 in freshwater populations, 9–11 in brackish water populations (in the Panama Canal region )
- Anal 8-10
- Pectoral 14
- Ventral 6
The black-mouthed larva has 25 to 30 scales in a central longitudinal row (mLR).
Way of life
Mollys are more warm than many other viviparous species and prefer temperatures between 24 ° C and 30 ° C and prefer pH values between 7.0 to 8.0. The Black Molly needs warmer water than its olive-colored natural relatives and trunk forms. In addition to plant-based food, the food spectrum of the black-muzzle also includes small crustaceans , insects and other invertebrates. The algae (including microzoo benthos in it) can be easily scraped off because the lower jaw is so flexible in itself (thanks to the cartilage rod) that the upper and lower teeth can enclose 120 ° with each other (see similar with Helostoma temminkii ).
The very peaceful species reproduces several times a year. After a gestation period of 26 to 35 days, 28 to 80 juvenile fish between six and eight millimeters in size are born. If there is enough food, the parents do not chase after their offspring.
Systematics
The taxonomic assessment of the black-muzzle is difficult. The species is polytypic and several of its partially highly differentiated populations have been described as separate species. These new species names were later declared to be synonyms. In some cases synonyms have also been revalidated, for example the mangrove molly ( Poecilia orri ) is given species rank again.
Cultivated forms
A number of breeding-influenced variants exist of the species, which was first introduced in Germany in 1899. In particular, the Black Molly, known since 1909, is widespread. The Black Molly is a cultivated form with a characteristic black, velvety sheen. What the cultivated forms have in common is a higher sensitivity compared to the wild form and an associated lower life expectancy. The breeding goals have been fixed by an international standard since 1989.
The cultivated forms vary, for example, according to the tail fin (forked tail or lyre) or according to the color: In addition to the black Black Mollys, there are also gold mollys, Dalmatian mollys (black and silver), pure silver mollys and other variants such as gold powder mollys and gold-black -Mollys. Especially with the silver molly and the silver marble molly, the breeding success is partly based on a hybridization with sailing parsons, so that these animals become larger and a slight addition of salt can be useful in the aquarium.
The variant Ballon Molly is considered a torture breed due to its S-shaped curved back .
Aquaristics
The aquarium hobby usually focuses on the black molly, which is popular as an ornamental fish. The agile, swimming and warmth loving Black Mollys need a pool of at least 120 centimeters in length and 100 liters for a species-appropriate attitude from a certain number of individuals. The diurnal animals find ideal living conditions with dense planting of aquatic flora (e.g. horn leaf ( Ceratophyllum ssp.) Has proven itself , as it forms a lot of oxygen and creates ideal environmental conditions) as a hiding place, v. a. for fry and young fish, and enough space as a swimming area. Black Mollys have pronounced social behavior and should therefore only be kept in groups of five to six specimens. As a gender ratio, two to three females per male should be aimed for. The females are usually very fertile and can reproduce several times a year. After a gestation period of approx. Four weeks, 30, 80 to a maximum of 100 young fish can be born. In this way, a strong population can develop in a relatively short time , which can degenerate through inbreeding . The parent animals do not care for the brood and sometimes eat the small larvae, so that the brood only has a certain chance of survival in the thicket of dense aquatic plants. An overhang of molly young fish can also be counteracted with predators in the aquarium.
Black Mollies are omnivorous, feed leaves to algae nursery, and can with vegetables particles , such as spinach , mashed peas , besides also chickweed , duckweed , fodder to be fed algae-based and commercial dry food. Additional animal foods such as enchytrae , Artemia , Cyclops , water fleas and mosquito larvae (white, red and black mosquito larvae) promote fish health in the long term. As a rule of thumb, only add as much feed in smaller quantities as it can be consumed before sinking. Overfeeding is to be avoided in any case, as food residues sinking to the bottom have a strong negative impact on the water quality and cause the nitrate levels to rise sharply. Excessive excretion of fish excrement and its breakdown products as a result of overfeeding also increase this value. Black Mollys are relatively sensitive to excessively high nitrate levels, which has a negative impact on their susceptibility to disease. To prevent this, efficient aquarium filtering, regular suction of sediment and sludge from the bonded floor and a 25% water change per week are recommended. Black Mollys require a constant water temperature between 25 to 28 degrees Celsius, a pH value of 7.5 to 8.2 and a water hardness of 18-30 dH °, as well as good water quality. In a community aquarium, this can be seen in the fact that Black Mollys are often the first species to react. Evidence of this are fins trapped on the body, lower activity or apathetic behavior on the ground. This can be counteracted by increasing the temperature to the ideal value, adding dosed sea salt and changing part of the water.
Black Mollys show pronounced social behavior. Keeping them in same-sex groups prevents uncontrolled mass reproduction. Only in the presence of females do adult males show pronounced courtship behavior towards females and aggression towards other rival males. ♂ Black Mollys harass and pursue females and try to stimulate them to reproduce by repeatedly touching their snouts on the belly. In practice, groups of four to five males have proven their worth, as they are engaged in rank fights and are less likely to harass the females.
A common disease that occurs when mollys and other ornamental fish are kept incorrectly is spotted disease ( ichthyophthiriosis ).
literature
- Günther Sterba : Freshwater fish in the world. Weltbild Verlag, Augsburg 1998, ISBN 3-89350-991-7 .
- Dieter Gentzsch: Poecilia sphenops. In: Claus Schaefer, Torsten Schröer (Hrsg.): The large lexicon of aquaristics. 2 volumes. Eugen Ulmer, Stuttgart 2004, ISBN 3-8001-7497-9 , pp. 791 f.
- Rüdiger Riehl , Hans A. Baensch : Aquariums Atlas. Volume 1, Mergus Verlag, Melle 2002, ISBN 3-88244-065-1 .
Individual evidence
- ^ Andreas Arnold: Naturalized fish species. Ziemsen Verlag, Wittenberg Lutherstadt 1990, ISBN 3-7403-0236-4 , p. 16.
- ^ Olaf Geiter, Susanne Homma, Ragnar Kinzelbach: Inventory and evaluation of neozoa in Germany. In: UBA texts. 25/02, 2002, ISSN 0722-186X , p. 29 ( PDF; 3.17 MB ).
- ↑ A. Gibb et al. (2008): Functional significance of intramandibular bending in Poeciliid fishes. - Environ. biol. fishes 83: 507-519.
- ↑ Balloon molly in the aquarium. DRTA archive
- ↑ Black-headed black- mouthed fish ( Poecilia sphenops )
- ↑ Black Molly ( Poecilia sphenops var. Black)
- ↑ Artemia nauplii are considered so-called "power food" in aquaristics due to their nutrient composition
- ↑ Black Mollys ( Poecilia sphenops ) STS leaflet. Instructions for animal welfare.
- ^ Mollys in the aquarium: species, breeding and rearing. DRTA archive
Web links
- Black Bear on Fishbase.org (English)