Pencil fish
Spitzmaul - pencilfish ( Nannostomus eques )
The pencilfish ( Nannostomus ) are a genus of fish from tropical South America that belongs to the family of the tribe Nannostomini Schlanksalmler ( Lebiasinidae ). The genus currently includes 19 described species.
Pencilfish are relatively small-growing, social -living fish of which many species are popular aquarium fish, due to their small size and contrasting color. From hunting and who also wrote the German common name, while the specificity of a very small mouth in the scientific naming reflects (Latin nannus = small, large stoma = mouth). In the English-speaking world the pencilfish be aptly called pencilfishes because of their pencil -like appearance.
Features
Pencilfish have a slender, elongated body with a rounded, sides scarcely flattened cross-section. Snout length is short, her mouth small, cramped and terminally. The standard length of adult animals depending on the type of only 1.6 to 6.5 cm.
The dentition of the genus Nannostomus shows in contrast to other genera of the family Lebiasinidae following characteristics: Zwischenkieferbein and lower jaw are covered with a series mehrspitziger incisors, while there is an additional second row of small conical teeth in the lower jaw. In addition, the Ziersalmlern lacks the frontal fontanelle. Some species have a dorsal fin, others lack this. Even within the same species there can be this difference.
Each type has an individual drawing pattern that is based on one, two or three dark longitudinal stripes: a primary strip in the middle of the body, a secondary blade in the back and a tertiary streaks in the abdominal region. The Tagfärbung differs in almost all types of clear night staining ( from cryptic ). The contrasting vertical stripes disappear almost completely and be replaced by a drawing pattern of spots or transverse bands.
Dissemination
Pencilfish occur in the catchment areas of large streams and rivers of tropical South America, such as the Amazon, Rio Negro and Orinoco top. The distribution area includes the states of Brazil, Venezuela, Colombia, Suriname, Guyana, French Guiana, Peru and Bolivia. The integration - pencilfish ( Nannostomus unifasciatus ) is an invasive species in Trinidad and Tobago.
Way of life
Pencilfish are quiet, slow swimmers and relatively shy animals. You prefer daytime stand in the upper and middle regions between water and plant roots and become active only under cover of dusk and go in search of food. They feed mainly on insects smallest falling on the water surface and from volunteers ( algae and micro- organisms contained therein ). Even if pencilfish are not schooling fish, they live in large social organizations. They are always seeking this visual contact with conspecifics, but keep it the same time using threats and simulated attacks on an individual distance.
Pencilfish biotopes are in larger rivers usually the low-flow, flat beaches and coves that have dense aquatic plants and their surface is partially covered with floating plants or floating leaves of submerged plants as well as smaller, weedy or shaded river with low flow. Most are black water rivers, rare clear-water rivers or mixed forms of black and clear water. Water hardness and conductivity are almost invariably extremely low and show a very acidic reaction ( pH values below 4). The water temperature is usually around 24 ° C, can occasionally but also rise to over 30 ° C.
System
M. Weitzman & Weitzman SH 2003 arranged the genus Nannostomus 16 species. 2009, 2011 and 2013 were described by A. Zarske three other species. More undescribed species are known.
The preferably obliquely floating spitzmaul - pencilfish ( Nannostomus eques ) and integration - pencilfish ( Nannostomus unifasciatus ) were formerly in genus Nannobrycon.
- Nannostomus anduzei Fernandez & Weitzman, 1987
- Längsbandziersalmler ( Nannostomus beckfordi ) Günther, 1872
- Two-band pencilfish ( Nannostomus bifasciatus ) Hoedeman, 1954
- Nannostomus britskii Weitzman, 1978
- Two strip - pencilfish ( Nannostomus digrammus ) ( Fowler, 1913)
- Spitzmaul - pencilfish ( Nannostomus eques ) Steindachner, 1876
- Shivers pencilfish ( Nannostomus espei ) ( Meinken, 1956)
- Nannostomus grandis Zarske, 2011
- Gold Tie- pencilfish ( Nannostomus harrisoni ) ( Eigenmann, 1909)
- Nannostomus limatus Weitzman, 1978
- Zwergziersalmler ( Nannostomus marginatus ) Eigenmann, 1909
- Marylins pencilfish ( Nannostomus marilynae ) Weitzman & Cobb, 1975
- Nannostomus minimus Eigenmann, 1909
- Purpurziersalmler ( Nannostomus mortenthaleri ) Paepke & Arendt, 2001
- Jewelry pencilfish ( Nannostomus nitidus ) Weitzman, 1978
- Nannostomus nigrotaeniatus Zarske, 2013
- Nannostomus rubrocaudatus Zarske, 2009
- Whitetail pencilfish ( Nannostomus trifasciatus ) Steindachner, 1876
- Embed - pencilfish ( Nannostomus unifasciatus ) Steindachner, 1876