''Nannostomus'', (from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

: ''nanos'' = small, and the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

: ''stomus'' = relating to the mouth), is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

belonging to the

characin Characiformes is an order of ray-finned fish, comprising the characins and their allies. Grouped in 18 recognized families, more than 2000 different species are described, including the well-known piranha and tetras.; Buckup P.A.: "Relationshi ...

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Lebiasinidae The pencil fishes are a family (Lebiasinidae) of freshwater fishes found in Costa Rica, Panama, and South America. They are usually small and are known as ornamental fishes in aquaria, including popular fishes such as the various pencil fish a ...

. All of the species in this genus are known as pencil fish or pencilfish, a popular name that was first only applied to two species in the 1920s, ''

Nannostomus unifasciatus ''Nannostomus unifasciatus'', (from the Greek: ''nanos'' = small, and the Latin ''stomus'' = relating to the mouth; from the Latin: ''unifasciatus'' = one band), commonly known as the one-lined pencilfish, is a freshwater species of fish belon ...

'' and ''

Nannostomus eques ''Nannostomus eques'', (from the Greek: ''nanos'' = small, and the Latin ''stomus'' = relating to the mouth; from the Latin: ''eques'' = horseman), commonly known as the diptail pencilfish or brown pencilfish, is a freshwater species of fish belo ...

'', but by the late 1950s would come to be applied to all members of the genus."Exotic Aquarium Fishes" by Dr. William T. Innes, Innes Publishing Co, Philadelphia, 1935"Pencilfishes" by William Vorderwinkler, TFH Publications, Neptune, NJ, 1956"Poecilobrycon unifasciatus" by Dr. William T. Innes, "The Aquarium," November 1940. Innes Publishing Co, Philadelphia Several of the species have become popular

aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

fish due to their attractive coloration, unique shape, and interesting demeanor.

Taxonomy

The genus ''Nannostomus'' was first erected by Günther in 1872 with the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

, '' Nannostomus beckfordi''. In 1876,

Steindachner Franz Steindachner (11 November 1834 in Vienna – 10 December 1919 in Vienna) was an Austrian zoologist, ichthyologist, and herpetologist. He published over 200 papers on fishes and over 50 papers on reptiles and amphibians. Steindachner describ ...

described three more species, ''

'', ''

'' (pictured below) and '' Nannostomus trifasciatus'' (pictured above). In 1909,

Carl H. Eigenmann Carl Henry Eigenmann (March 9, 1863 – April 24, 1927) was a German-American ichthyologist of the late nineteenth and early twentieth centuries, who, along with his wife Rosa Smith Eigenmann, and his zoology students is credited with identifyin ...

described '' Nannostomus marginatus'', '' Nannostomus minimus'', and '' Nannostomus harrisoni''. All but ''N. minimus'' have been popular with aquarists since the early 20th century, in part due to enthusiastic articles written about them, and photographs taken of them, by

William T. Innes William Thornton Innes III, L.H.D. (February 2, 1874 – February 27, 1969) was an American aquarist, author, photographer, printer and publisher. Innes was the author of numerous influential books and hundreds of articles about aquarium fish, aqua ...

that were published as early as 1933. Over the years, the genus was split by subsequent authors into other genera, including ''Poecilobrycon'' and ''Nannobrycon''. After nearly a century of debate on the subject, Dr. Stanley H. Weitzman and Dr. J. Stanley Cobb restored earlier taxonomy and expanded upon it, unifying all species under ''Nannostomus'' in 1975. This comprehensive revision of the genus has now been widely accepted. Dr. Weitzman is also responsible for the description of five of the more recently introduced species, '' Nannostomus marilynae'', '' Nannostomus limatus'', ''Nannostomus nitidus,'' '' Nannostomus britskii'', and '' Nannostomus anduzei''. Nineteen species are now known, most of which are also familiar to aquarists. Several other unidentified ''Nannostomus'' species have been imported over the years; many were found as bycatch with other small characins, but their taxonomic status is yet to be determined.

Species

The 19 currently recognized species in this genus are: * '' Nannostomus anduzei''

Fernández Fernández () is a Spanish surname meaning "son of Fernando". The Germanic name that it derives from ( Gothic: ''Frið-nanð'') means "brave traveler." The Portuguese version of this surname is Fernandes. The Arabized version is ''Ibn Faranda' ...

& S. H. Weitzman, 1987 * '' Nannostomus beckfordi'' Günther, 1872 (golden pencilfish) * '' Nannostomus bifasciatus'' Hoedeman, 1954 (two-lined pencilfish,whiteside pencilfish) * '' Nannostomus britskii'' S. H. Weitzman, 1978 (spotstripe pencilfish) * '' Nannostomus digrammus'' ( Fowler, 1913) (two-stripe pencilfish) * ''

, 1876 (brown pencilfish,diptail) * '' Nannostomus espei'' ( Meinken, 1956) (Espe's pencilfish,barred pencilfish) * '' Nannostomus grandis'' Zarske, 2011Zarske, A. (2011): Nannostomus grandis ''spec. nov. – ein neuer Ziersalmler aus Brasilien mit Bemerkungen zu'' N. beckfordi ''GÜNTHER, 1872,'' N. anomalus ''STEINDACHNER, 1876 und'' N. aripirangensis ''MEINKEN, 1931 (Teleostei: Characiformes: Lebiasinidae).'' Vertebrate Zoology, 61 (3): 283–298. * '' Nannostomus harrisoni'' ( C. H. Eigenmann, 1909) (Harrison's pencilfish,blackstripe pencilfish) * '' Nannostomus limatus'' S. H. Weitzman, 1978 (elegant pencilfish) * '' Nannostomus marginatus'' C. H. Eigenmann, 1909 (dwarf pencilfish) * '' Nannostomus marilynae'' S. H. Weitzman & Cobb, 1975 (Marilyn's pencilfish,greenstripe pencilfish) * '' Nannostomus minimus'' C. H. Eigenmann, 1909 (least pencilfish) * '' Nannostomus mortenthaleri'' Paepke &

Arendt Hannah Arendt (, , ; 14 October 1906 – 4 December 1975) was a political philosopher, author, and Holocaust survivor. She is widely considered to be one of the most influential political theorists of the 20th century. Arendt was born ...

, 2001 (coral-red pencilfish) * '' Nannostomus nigrotaeniatus'' Zarske, 2013Zarske, A. (2013)
''Nannostomus nigrotaeniatus'' spec. nov. – ein neuer Ziersalmler aus Venezuela (Teleostei: Characiformes: Lebiasinidae).
''Vertebrate Zoology, 63 (2): 125–137.'' (in German) * '' Nannostomus nitidus'' S. H. Weitzman, 1978 (shining pencilfish) * '' Nannostomus rubrocaudatus'' Zarske, 2009(purple pencilfish) * '' Nannostomus trifasciatus''

, 1876 (three-stripe pencilfish) * ''

, 1876 (one-line pencilfish)

Description

Most species are slender, pencil-shaped fish ranging in size from under 1 to about 2 in long. ''N. marginatus'', ''N. rubrocaudatus'', and ''N. mortenthaleri'' possess shortened, blockier outlines reminiscent of pencil stubs. All but one species, ''Nannostomus espei'', possess one to five horizontal black or brown stripes with gold or silver iridescence appearing dorsal to the primary stripe. Most also display red, orange, or maroon highlights in their fins, and many have flashes of these colors on their flanks as well. The recently described ''N. mortenthaleri'' and ''N. rubrocaudatus'' are especially vividly colored. For ''N. espei'' alone, horizontal stripes are only weakly present and are supplanted by five dark comma-shaped blotches. This pattern is assumed by other species at night, but only ''N. espei'' displays the pattern permanently and in daylight. The

adipose fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as s ...

is present in some species and absent in others, while in certain species, such as ''N. eques'', it may be present or absent within the species. All swim in a horizontal attitude except ''N. unifasciatus'' and ''N. eques'', which assume an oblique, 'snout-up' posture. A range of

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

occurs in the genus, with males being more brilliantly colored in some species, especially with regard to color present in the fins, and far less evident in other species. However, a reliable indicator of gender for most of the species rests in the

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

of adult males, which is enlarged and elongated (as in ''N. espei'', ''N. eques'', etc.) and/or the anal fin of males is more colorful (as in ''N. harrisoni'', ''N. marginatus,'' etc.). The popular aquarium species, ''N. trifasciatus'', is an exception in this regard.

Distribution

The genus has a vast distribution in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

, from

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

, and the

Guyanas The Guianas, sometimes called by the Spanish loan-word ''Guayanas'' (''Las Guayanas''), is a region in north-eastern South America which includes the following three territories: * French Guiana, an overseas department and region of France * G ...

in the north, to the southern

Amazon basin The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries of Bolivi ...

and

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

in the south, to

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

in the west, and

Belém Belém (; Portuguese for Bethlehem; initially called Nossa Senhora de Belém do Grão-Pará, in English Our Lady of Bethlehem of Great Pará) often called Belém of Pará, is a Brazilian city, capital and largest city of the state of Pará in t ...

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, in the east. Several of the individual species have a distribution nearly as vast. As a result, many of the species are polymorphic and manifest marked color variations depending on the population. Over the years, some of these color variants have been erroneously described as separate species. Such names as 'Nannostomus ocellatus', 'N. anomalus' and 'N. auratus', among many others, are now known to be

junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...

s for the various species. To date, only two species, ''N. beckfordi'' and ''N. harrisoni'', have been commercially raised for the aquarium trade in fisheries, mostly in

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

. All of the remaining species that find their way to home aquaria are wild-caught from South American waters.

In the aquarium

''Nannostomus'' species thrive in home aquaria when provided with soft, moderately acidic water, low nitrate levels, and temperatures in the range of 22 to 28 °C. The addition of

aquatic plants Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...

, including floating varieties, is recommended. The latter reduces the likelihood of fish jumping, which is a common occurrence for some of the species, especially ''N. espei'' and ''N. unifasciatus''. They should be kept in schools of at least six. If kept in a

community aquarium Community aquaria are tanks that are designed to contain more than one species of fish. Most commonly they include a variety of species that do not normally occur together in nature, for example angelfish from Brazil, swordtails from Mexico, and ...

, the best tankmates are other species of ''Nannostomus,'' small peaceful

s, and

corydoras ''Corydoras'' is a genus of freshwater catfish in the family Callichthyidae and subfamily Corydoradinae. The species usually have more restricted areas of endemism than other callichthyids, but the area of distribution of the entire genus almost ...

. Aquaria with a strong water current, large tankmates, or swift-moving species are contraindicated. If kept in a thickly planted single-species aquarium with the above water parameters, most species will spawn, eggs will not be eaten, and the fry will be found among the floating plants. Baby

brine shrimp ''Artemia'' is a genus of aquatic crustaceans also known as brine shrimp. It is the only genus in the family Artemiidae. The first historical record of the existence of ''Artemia'' dates back to the first half of the 10th century AD from Urmia La ...

, live or frozen, and other small-sized foods are required for both fry and adults. They are also avid

biofilm A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular ...

grazers and, for most of the species,

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

are under-reported staples of their diet. In most species, the males establish small territories and defend them. Their defensive actions are usually harmless, but in two species, ''N. mortenthaleri'' and ''N. trifasciatus'', antagonistic behavior directed at

conspecific Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species. Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organ ...

s can have deleterious results if sufficient space and plant cover are not provided. Once acclimated to the aquarium and provided with suitable conditions, they are hardy, often living for five or more years.

References

Introduction To The Fish Families 2004
Popular Freshwater Tropical Fish. Accessed on June 24, 2005. * * Innes, Dr William T. EXOTIC AQUARIUM FISHES, 1st edition. Innes Publishing Co. Philadelphia, 1935 * Weitzman, Dr. Stanley H. and Cobb, Dr. J. Stanley, ''A Revision of the South American Fishes of the Genus Nannostomus'', Smithsonian Contributions to Zoology, #186. Smithsonian Institution Press. Washington, D.C. 1975. * Weitzman, Dr. Stanley H. ''Review of South American Characid Fishes of Subtribe Nannostomina'', Proceedings of the United States National Museum, Smithsonian Press. Washington, D.C. 1966 * Weitzman, Dr. Stanley H. ''Three New Species of Fishes of the Genus Nannostomus from the Brazilian States of Para and Amazonas'', Smithsonian Contributions to Zoology, #263. Smithsonian Institution Press. Washington, D.C. 1978. {{Taxonbar, from=Q1766413 Lebiasinidae Fishkeeping Freshwater fish of South America Taxa named by Albert Günther Vertebrates of Guyana