Synonyms
- Nannostomus anomalus Steindachner, 1876;
- Nannostomus aripirangensis Meinken, 1931;
- Nannostomus simplex Eigenmann, 1909;
- Nannostomus beckfordi surinami Hoedeman, 1954
Etymology
The scientific name “Nannostomus” comes from a combination of two words: “nannus”, which means small in Latin, and “stoma”, which means mouth in Greek. This name refers to the small size of the mouthparts of the fish species belonging to this genus.
The species name “beckfordi” is named after a person named F. J. B. Beckford, who was the first person to collect and present this particular species to the British Museum. This name is used as a way to honor Beckford’s contributions to the study of this species and to recognize his role in discovering and preserving this important specimen for future generations to study.
Classification
- Order: Characiformes
- Family: Lebiasinidae
Distribution
The type locality of this species is a plantation called “Goedverwagting” on the coast of Demerara, located in Guyana. However, this particular species is widely distributed throughout the rivers of Guyana, Suriname, and French Guiana, as well as in the eastern Amazon drainage in Amapá and Pará states in Brazil.
In addition to these locations, this species has also been reported from the rio Madeira, lower and middle Amazon, as far upstream as the lower rio Negro, and Río Orinoco in Venezuela. This indicates a wide distribution range for the species across multiple countries and river systems.
While wild populations of this species are still exported on a regular basis, many of the individuals that are sold in the aquarium trade are commercially farmed. This suggests that this species is a popular choice among aquarium enthusiasts and is being bred in captivity to meet demand.
It is important to note that wild populations of this species display variations in their color patterns depending on their geographic origin. Some of these populations have even been described as distinct species in the past. This highlights the need for continued research on this species and its populations, in order to better understand its distribution, ecology, and potential conservation status.
Habitat
This groups of fish is known to inhabit slow-moving tributaries, small rivers, and swampy areas. It is particularly common in areas that have dense growth of aquatic vegetation, as well as submerged woody structures and leaf litter.
These types of environments provide the fish with the necessary shelter and food sources to survive. The aquatic vegetation offers protection from predators and also serves as a source of food for the fish, while the submerged woody structures and leaf litter provide additional hiding places and areas for the fish to forage.
The species is adapted to living in areas with low water flow and high organic content, which is typical of swampy environments. These habitats are often nutrient-rich and support a variety of other aquatic life, which the fish can feed on.
Overall, this species has evolved to thrive in specific environmental conditions and is well-suited to living in habitats with a particular set of characteristics, such as slow-moving water, abundant aquatic vegetation, and submerged woody structures and leaf litter.
Maximum Standard Length
The Maximum Standard Length of this fish species is typically reported to be around 30-35 mm. However, some sources suggest that it can grow up to a length of 65 mm.
It is important to note that the reported size range can vary depending on the source and the specific population being studied. Additionally, factors such as diet, environmental conditions, and genetics can also impact the growth and size of individual fish.
Despite this variation, it is generally accepted that the Maximum Standard Length of this species falls within the range of 30-35 mm. However, the potential for some individuals to reach up to 65 mm in length indicates that there is a degree of flexibility in the size range of this species.
Aquarium Size
To provide a suitable environment for this fish species in an aquarium setting, it is recommended that the base dimensions of the tank be at least 45 x 30 cm or equivalent. However, it is important to note that larger housing is recommended if you intend to keep multiple males together.
Providing adequate space in the aquarium is crucial for the health and well-being of the fish. A larger tank will not only allow the fish to move around freely, but it will also help to reduce territorial conflicts between males, which can occur when space is limited.
It is important to consider the needs of the specific species when selecting an appropriate tank size. Factors such as the size of the fish, their behavior, and their natural habitat should all be taken into account to ensure that the aquarium environment is suitable for the fish.
In summary, a base tank size of 45 x 30 cm or equivalent is necessary to provide adequate space for this fish species. Larger housing is recommended if you plan to keep multiple males together to reduce territorial conflicts and promote healthy social behavior.
Maintenance
To maintain optimal health and well-being, this species should ideally be kept in a heavily-planted set-up with a dark substrate. The presence of dense vegetation in the aquarium provides the fish with a sense of security and allows them to display natural behavior. In addition, the broken lines of sight in a planted aquarium can help reduce skittishness and improve the overall well-being of the fish.
Floating plants are a useful addition to the aquarium, as they provide additional shelter and create a natural-looking environment. Driftwood branches and dried leaf litter are also beneficial, as they promote the establishment of microbe colonies during decomposition. These microorganisms can provide a valuable secondary food source for fry, while the tannins and other chemicals released by the decaying leaves are thought to be beneficial for the overall health of the aquarium.
When it comes to filtration, a gentle air-powered sponge-style unit is typically adequate, although a degree of water movement is acceptable. It is important to ensure that the filtration system is appropriate for the size of the aquarium and the number of fish being kept. Regular water changes are also important to maintain water quality and ensure the health of the fish.
Overall, a heavily-planted aquarium with a dark substrate, floating plants, driftwood branches, and dried leaf litter is ideal for this fish species. Appropriate filtration and regular maintenance will help ensure the health and well-being of the fish in the aquarium.
Water Conditions
Maintaining appropriate water conditions is crucial for the health and well-being of this fish species. The following guidelines are recommended for optimal care:
- Temperature: The recommended temperature range for this species is between 21-27°C. It is important to maintain a consistent temperature within this range to avoid any fluctuations that could stress the fish.
- pH: The ideal pH range for this species is between 5.0-8.0, although wild fish may do best towards the lower end of this range. It is important to note that fluctuations in pH can be harmful to the fish, so it is important to monitor and maintain a stable pH level within the recommended range.
- Hardness: The recommended hardness range for this species is between 18-268 ppm. The appropriate hardness level may vary depending on the origin of the fish, so it is important to research and adjust the hardness levels accordingly.
It is important to note that maintaining appropriate water conditions is crucial for the health and well-being of the fish. Regular monitoring of water quality and maintenance of appropriate conditions, including temperature, pH, and hardness levels, is essential to ensure the health and longevity of the fish in the aquarium.
Diet
The diet of this fish species consists mainly of tiny invertebrates and zooplankton in its natural habitat. As a micropredator, it feeds on small organisms that are suitable for its small mouthparts.
In an aquarium setting, this species will accept dried foods of a suitable size. However, to provide a balanced and nutritious diet, it is important to offer daily meals of small live and frozen fare, such as Artemia nauplii, Moina, grindal worm, and similar small organisms.
Offering a variety of food sources will help ensure that the fish receive the necessary nutrients to maintain their health and well-being. It is important to note that overfeeding should be avoided, as it can lead to health issues and a deterioration in water quality.
Overall, providing a balanced diet consisting of both dried and live/frozen food sources will help ensure the health and longevity of this fish species in an aquarium setting.
Behaviour and Compatibility
This fish species is relatively peaceful and does not compete well with very boisterous or much larger tankmates. In a community setting, it is best kept with similarly-sized, peaceful characids and smaller callichthyid or loricariid catfishes. However, sedate surface-dwellers such as hatchetfishes are best omitted, especially in smaller aquariums, as they may be too active and potentially stress the fish.
This species also makes an ideal dither fish for Apistogramma spp. and other dwarf cichlids. It tends to inhabit the middle-to-upper regions of the tank and does not often predate fry, making it a suitable companion for these types of fish. In a more general community set-up, it can be combined with smaller rasboras, barbs, anabantoids, and similar species.
When keeping this species, it is recommended to purchase as many individuals as possible, ideally 10 or more. Keeping a larger group helps to spread any aggression between individuals and encourages bolder behavior, resulting in more natural behavior and a healthier social dynamic among the fish.
Overall, this species is relatively peaceful and is best kept with smaller, peaceful tankmates. It also makes an excellent dither fish for dwarf cichlids and can be combined with a variety of other small fish species in a community setting.
Sexual Dimorphism
Distinguishing between male and female individuals of this fish species is relatively straightforward. Adult males are generally more intensely colored, particularly when in spawning condition, while females have a rounder body shape.
Additionally, the anal fin of the male has a curved posterior edge, which is straight in females. This difference in anal fin shape can be a useful visual clue for identifying the sex of the fish.
Overall, the physical differences between male and female individuals of this species are relatively subtle, but can be useful for distinguishing between the sexes. By observing the coloration, body shape, and anal fin shape, it is possible to identify male and female individuals of this species.
Reproduction
This fish species is an egg-scattering free spawner and exhibits no parental care. When in good condition, adult fish will spawn often, and in a mature aquarium, small numbers of fry may appear without intervention. However, to maximize yield, a more controlled approach is required.
To create an environment suitable for spawning, a smaller aquarium should be set up and filled with mature water. The aquarium should be very dimly lit and the base covered with some kind of mesh that is large enough to allow the eggs to fall through but small enough to prevent the adults from reaching them. Plastic ‘grass’-type matting or a layer of glass marbles can also be used as a suitable substrate. Alternatively, filling much of the tank with a fine-leaved plant such as Taxiphyllum spp. or spawning mops can also return decent results.
The water in the spawning tank should be slightly acidic to neutral pH with a temperature towards the upper end of the range suggested above. An air-powered sponge filter or air stone(s) should also be included to provide oxygenation and water movement.
Once the adult fish are well-conditioned, a single pair or group comprising one or two males and several females can be introduced to each container. It’s worth noting that the more individuals involved, the greater the risk of egg predation, and males may distract each other from females if there is more than one in the tank.
After 2-3 days, the adults can be removed, and the first fry should be visible around 3 days later. The initial food for the fry should be Paramecium or a proprietary dry food of a small enough grade, and once the fry are large enough to accept them, Artemia nauplii, microworm, etc., can be introduced.
It’s worth noting that this section is in memory of the late expert fish-breeder, Alan P. Vaissiere, who assisted extensively with the information presented here.
In summary, this species of fish can be bred in a controlled environment with a smaller aquarium set up for spawning. Creating a suitable substrate and maintaining appropriate water conditions are crucial for maximizing yield. A single pair or group of fish can be introduced to each container, and the adults should be removed after 2-3 days. The first fry should be visible approximately 3 days later and can be fed appropriately-sized food.
Notes
Nannostomus beckfordi, commonly known as Beckford’s pencilfish or brown pencilfish, is the type species of the Nannostomus genus. It is widely available in the aquarium trade and is an excellent choice for novice fish keepers as it is less demanding compared to most of its relatives. This fish is sometimes referred to as ‘Beckford’s pencil fish’ or ‘brown pencilfish’.
In the original description by Günther, the color pattern of N. beckfordi was described as having a silvery band along the middle of the side, bordered above by a reddish band and below by a blackish band, with a black spot on the lower half of the gill cover and a red caudal fin. However, this fish is found in various color forms across its range, and some of these have previously been described as distinct species. Despite this, all these forms are currently considered synonymous with N. beckfordi. The following color forms were described as distinct species in the past:
- N. anomalus Steindachner, 1876: Its type locality is Óbidos in the middle Amazon, near Santarém. Its dark lateral stripe does not reach the caudal-fin and is bordered above and below by narrow silver stripes. The upper part of the body is brownish, and the lower part is yellowish. This coloration is similar to that of N. grandis Zarske, 2011.
- N. aripirangensis Meinken, 1931: Described from Arapiranga Island, near Belém, Pará state, Brazil. This color form is commonly found in the aquarium hobby. Its base body coloration is dark brown, and the dark lateral band extends into the central caudal-fin rays. The remainder of the caudal-fin base is reddish, and the ventral fins are red with light blue to whitish tips.
- N. simplex Eigenmann, 1909: Described from ‘Lama Stop-off, Guyana’. The original description describes a fish with a dark grey dorsal surface with a median dark line; a light band from snout to base of upper rays of middle of caudal-fin; a black band through mandibles and snout to base of lower caudal-fin and continued on the two middle rays; ventral surface plain, except for a spot between the tips of the ventral fins; chromatophores of the lateral band scattered above the pectoral fins and front part of the anal-fin.
- N. beckfordi surinami Hoedeman, 1954: Described from Berg en Dal, just north of Brokopondo reservoir, Suriname. The original description is unavailable, and this subspecies was synonymized with N. beckfordi by Weitzman (1966) without explanation.
As the type species of the genus and a popular aquarium fish, N. beckfordi is a great choice for beginner fishkeepers since it is less demanding than most congeners.
In addition to the main species of the genus, N. beckfordi, there are other species that have been confused with it in the past. N. minimus was considered a synonym of N. beckfordi, while N. grandis was thought to be very similar to N. anomalus, which was exported under that name in the early 20th century. A description of N. grandis by Zarske in 2011 identified N. anomalus as synonymous with N. beckfordi because the original description by Steindachner was deemed uninformative and lacked illustrations, and the type specimens have been lost.
It is worth noting that Nannostomus species often change color at night, adopting a cryptic, vertically-barred pattern. This means that the fish may look different when you switch on the aquarium lights after dark or in the morning.
Lebiasinidae is a family of fish within the order Characiformes, which is sometimes divided into the subfamilies Lebiasininae and Pyrrhulininae. These fish are characterized by their long, elongated body shape, with 17-33 scales in the lateral series and a laterosensory canal system that is absent or reduced to 7 scales or less. Some species have an adipose fin, while others do not, and the anal fin has a relatively short base of 13 scales or less. In most species, males have an enlarged or well-developed anal fin used in courtship and spawning.
Other distinguishing features of Lebiasinidae include the absence of a frontal/parietal fontanelle, the cheek being well-covered by the orbital and opercular bones, the absence of a supraoccipital crest, and the dorsal body scales beginning over the parietal bones.
Characiformes is one of the most diverse orders of freshwater fish, with nearly 2,000 valid species distributed among 19 families. This diversity has made it difficult for researchers to resolve genetic relationships, with many genera remaining incertae sedis. In many cases, exhaustive study of individual species is the only way to resolve these problems.
Modern molecular phylogenetic techniques have allowed some progress, with a 2005 research paper by Calcagnotto et al. proposing some interesting hypotheses. According to their results, Lebiasinidae forms a trans-Atlantic, monophyletic clade alongside the families Ctenoluciidae and Hepsetidae. This clade is further related to Alestidae. Other studies, such as Oliveira et al. in 2011, suggest that the family Erythrinidae is also closely related to this grouping, with Hepsetidae and Alestidae more distantly related.
References
- Günther, A., 1872 – Proceedings of the Zoological Society of London 1872 (pt 1): 146
On a new genus of characinoid fishes from Demerara. - Calcagnotto, D., S. A. Schaefer, and R. DeSalle, 2005 – Molecular Phylogenetics and Evolution 36(1): 135-153
Relationships among characiform fishes inferred from analysis of nuclear and mitochondrial gene sequences. - Eigenmann, C. H., 1909 – Annals of the Carnegie Museum 6(1): 4-54
Reports on the expedition to British Guiana of the Indiana University and the Carnegie Museum, 1908. Report no. 1. Some new genera and species of fishes from British Guiana. - Oliveira, C. A., G. S. Avellino, K. T. Abe, T. C. Mariguela, R. C. Benine, G. Orti, R. P. Vari, and R. M. Corrêa e Castro, 2011 – BMC Evolutionary Biology 11(1): 275-300
Phylogenetic relationships within the speciose family Characidae (Teleostei: Ostariophysi: Characiformes) based on multilocus analysis and extensive ingroup sampling. - Steindachner, F., 1876 – Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften. Mathematisch-Naturwissenschaftliche Classe v. 74 (1. Abth.): 49-240
Ichthyologische Beiträge (V). - Weitzman, S. H., 1966 – Proceedings of the United States National Museum v. 119 (no. 3538): 1-56
Review of South American characid fishes of subtribe Nannostomina. - Weitzman, S. H. and J. S. Cobb, 1975 – Smithsonian Contributions to Zoology 186: i-iii + 1-36
A revision of the South American fishes of the genus Nannostomus Günther (family Lebiasinidae). - Zarske, A., 2011 – Vertebrate Zoology 61(3): 283-298
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).
