Nannostomus beckfordi GÜNTHER, 1872

Golden Pencilfish

SynonymsTop ↑

Nannostomus anomalus Steindachner, 1876; Nannostomus aripirangensis Meinken, 1931; Nannostomus simplex Eigenmann, 1909; Nannostomus beckfordi surinami Hoedeman, 1954

Etymology

Nannostomus: from the Latin nannus, meaning ‘small‘, and Greek stoma, meaning ‘mouth’, in reference to the small mouthparts of member species.

beckfordi: named for F. J. B. Beckford who first collected this species and presented it to the British Museum.

Classification

Order: Characiformes Family: Lebiasinidae

Distribution

Type locality is ‘Goedverwagting, a plantation on the Coast of Demerara, Guyana’ but this species is widely-distributed throughout rivers of Guyana, Suriname, and French Guiana, plus the eastern Amazon drainage in Amapá and Pará states, Brazil.

It’s also reported from the rio Madeira, lower and middle Amazon as far upstream as the lower rio Negro, and Río Orinoco in Venezuela.

Though wild fish are still exported on a regular basis, many of those seen on sale in the aquarium trade are farmed commercially.

Wild populations vary in colour pattern depending on origin, and some populations have previously been described as distinct species (see ‘Notes’).

Habitat

Inhabits sluggish tributaries, small rivers and swampy areas, particularly in areas with dense growth of aquatic vegetation or submerged woody structures and leaf litter.

Maximum Standard Length

30 – 35 mm, although some sources suggest it can attain 65 mm.

Aquarium SizeTop ↑

Base dimensions of at least 45 ∗ 30 cm or equivalent are necessary, with larger housing recommended if you wish to keep multiple males together.

Maintenance

Should ideally be kept in a heavily-planted set-up, preferably with a dark substrate.

The broken lines of sight that exist in such a display allow it to display natural behaviour as well as helping to reduce skittishness.

Floating plants are a useful addition as are driftwood branches and dried leaf litter, the latter in particular driving establishment of microbe colonies as decomposition occurs.

Such microorganisms can provide a valuable secondary food source for fry, whilst the tannins and other chemicals released by the decaying leaves are also thought beneficial.

Filtration need only be gentle with an air-powered sponge-style unit normally adequate, although a degree of water movement is acceptable.

Water Conditions

Temperature: 21 – 27 °C

pH: 5.0 – 8.0, though wild fish may do best towards the lower end of this range.

Hardness: 18 – 268 ppm; notes for wild fish as per pH.

Diet

A micropredator feeding on tiny invertebrates and other zooplankton in nature.

In the aquarium it will accept dried foods of a suitable size but should also be offered daily meals of small live and frozen fare such as Artemia nauplii, Moina, grindal worm, etc.

Behaviour and CompatibilityTop ↑

Relatively peaceful and will not  compete well with very boisterous or much larger tankmates.

In a community it’s best kept with similarly-sized, peaceful characids and smaller callichthyid or loricariid catfishes but sedate surface-dwellers such as hatchetfishes are best omitted, especially in smaller aquaria.

It also makes an ideal dither fish for Apistogramma spp. and other dwarf cichlids since  it tends to inhabit the middle-to-upper regions of the tank, and does not often predate fry.

In a more general community set-up it can be combined with smaller rasboras, barbs, anabantoids, etc.

Buy as many as possible, ideally 10 or more, as when kept in larger groups any aggression is spread between individuals plus the fish are bolder and exhibit more natural behaviour.

Sexual Dimorphism

Adult males are more intensely-coloured, especially when in spawning condition, while females are noticeably rounder-bodied.

The anal-fin of the male has a curved posterior edge which is straight in females.

Reproduction

An egg-scattering free spawner exhibiting no parental care.

When in good condition adults will spawn often and in a mature aquarium it’s possible that small numbers of fry may start to appear without intervention.

However if you want to maximise yield a more controlled approach is required.

The adult group can still be conditioned together but a smaller aquarium should also be set up and filled with mature water.

This should be very dimly lit and the base covered with some kind of mesh of a large enough grade so that the eggs can fall through but small enough so that the adults cannot reach them.

The widely available plastic ‘grass’-type matting can also be used and works well, as does a layer of glass marbles.

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 itself should be of 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.

When the adult fish are well-conditioned a single pair or group comprising one or two males and several females can then be introduced to each container, though it’s worth noting that the more individuals involved the greater the risk of egg predation, plus males may distract each other from females if there’s more than one in the tank.

The adults can be removed after 2-3 days and the first fry should be visible around 3 days later.

Initial food should be Paramecium or a proprietary dry food of sufficiently small (5-50 micron) grade, introducing Artemia nauplii, microworm, etc., once the fry are large enough to accept them.

In memory of late expert fish-breeder Alan P. Vaissiere who assisted extensively with this section.

NotesTop ↑

This is the type species of the genus, fairly ubiquitous in the aquarium trade, and represents an excellent choice for the newcomer to fishkeeping since it’s less demanding than most congeners.

It’s sometimes referred to as ‘Beckford’s pencil fish’ or ‘brown pencilfish’.

In the original description the colour pattern of N. beckfordi is given by Günther as ‘a silvery band along the middle of the side, bordered above by a reddish, and below by a blackish band. A black spot on the lower half of the gill cover. Caudal-fin red’.

However, it exists in a number of different colour forms across its range of which the following have been described as distinct species in the past.

All are currently considered synonymous with N. beckfordi.

N. anomalus Steindachner, 1876: type locality is Óbidos in the middle Amazon, close to Santarém. The 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, lower part yellowish. This description appears to correspond closely with that of N. grandis Zarske, 2011 (see below).

N. aripirangensis Meinken, 1931: described from Arapiranga Island, close to Belém, Pará state, Brazil. This appears to be the common form in the aquarium hobby. Base body colouration 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. We’ve been unable to obtain the original description and this subspecies was synonymised with N. beckfordi by Weitzman (1966), apparently without explanation as to why.

In addition the valid species N. minimus has been considered a synonym of N. beckfordi in the past, while N. grandis appears very close to Steindachner’s  N. anomalus and was exported as such in the early 20th century.

In the description of N. grandis Zarske (2011) considered N. anomalus synonymous with N. beckfordi as he considered Steindachner’s description of N. anomalus to be uninformative and lacking illustrations, plus the type specimens have been lost.

Don’t worry if your fish look different when you switch on the aquarium lights after dark or in the morning as like most Nannostomus species it assumes a cryptic, vertically-barred colour pattern at night.

This diurnal rhythm has been show to occur in blind specimens, suggesting it’s an automatic response that the fish cannot control.

The family Lebiasinidae is included in the order Characiformes and sometimes split into the nominal subfamilies Lebiasininae and Pyrrhulininae, though there has not been a major review of the grouping in recent times.

All lebiasinid genera possess a relatively long, elongate body shape with 17-33 scales in the lateral series and laterosensory canal system 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 the majority of members males have an enlarged or otherwise well-developed anal-fin used in courtship and spawning.

The frontal/parietal fontanelle is always absent, the cheek well-covered by the orbital and opercular bones, the supraoccipital crest is absent, and the scales of the dorsal body begin over  the parietal bones.

Characiformes is among the most diverse orders of freshwater fishes currently including close to 2000 valid species distributed among 19 families.

This tremendous taxonomical and morphological diversity has historically impaired the ability of researchers to resolve their genetic relationships with many genera remaining incertae sedis.

A further limiting factor has been that in many cases exhaustive study of these on an individual basis is the only way to resolve such problems.

Modern molecular phylogenetic techniques have allowed some headway, though, and a research paper by Calcagnotto et al. published in 2005 revealed some interesting hypotheses.

Their results suggest that Lebiasinidae forms a trans-atlantic, monophyletic clade alongside the families Ctenoluciidae and Hepsetidae, this clade further forming a sister group to Alestidae.

Others such as Oliveira et al. (2011) have concluded that the family Erythrinidae is also closely-related to this grouping with Hepsetidae and Alestidae more distant.

References

1. Günther, A., 1872 - Proceedings of the Zoological Society of London 1872 (pt 1): 146
   On a new genus of characinoid fishes from Demerara.
2. 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.
3. 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.
4. 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.
5. Steindachner, F., 1876 - Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften. Mathematisch-Naturwissenschaftliche Classe v. 74 (1. Abth.): 49-240
   Ichthyologische Beiträge (V).
6. 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.
7. 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).
8. 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).