Diptail Pencilfish
Nannostomus eques
The 'head-up' Pencilfish. Famous for hovering at a 45-degree angle in synchronized schools. An incredibly peaceful, slow-moving fish that will easily starve to death if housed with fast, greedy tankmates.
Wassertemperatur
23 - 28 °C
pH-Wert
5.5 - 7
Wassertyp
Süßwasser
Tankfüllstand
Oberfläche
Erwachsenengröße
5 cm
Mindesttankvolumen
>= 60 L
Mindestgruppe
>= 6
GH
1 - 10 dGH
KH
1 - 5 dKH
TDS
25 - 200 ppm
Leitfähigkeit
39 - 313 uS/cm
Artbeschreibung
Geographical Origin and Habitat: Central Amazon Basin (Brazil, Peru, Colombia). Exclusively populate the surface of swamps ("Igapó") and slow streams (Igarapés), hiding under huge floating carpets (Salvinia, Pistia).
Taxonomy and Morphology: Brown Pencilfish / Diptail (Nannostomus eques). The king of imitation: shape and posture replicate a twig. Superior mouth (to eat from under the surface of the water) and short digestive tract.
Social Behavior: Unmistakable posture: they swim (or rather "hang") inclined at 45 degrees with their snout pointing upwards to the surface. They move in jerks all together (schools of 10+), giving the illusion of debris drifting adrift.
Coloration and Sexual Dimorphism: Woody brownish color on top, with an opaque silvery belly for camouflage against predators from below. At night the dark stripes fade into oblique patches. Males have a much more intense red/brown coloration on the anal fin.
Pflege, Zucht und Mitbewohner
Aquarium Setup: Tank (minimum 80 cm / 32 inches) strictly filled with floating plants and Pistia. If kept under bare light (without floaters) they will perish from stress darting away at the first passage of shadows. No strong surface current or they won't be able to stay in trim (45 degrees).
Diet and Feeding: Specialized surface hunter. They wait motionless for midges or springtails to fall on the water. In the tank they eat Drosophila, pulverized high-end flakes floating, or freeze-dried micro pellets (as long as they don't sink).
Water Quality: Acidic Blackwater. They are extremely prone to parasites if the water is alkaline (Ph > 7.0). The tannins released by the dry leaves on the bottom are indispensable as a natural antibacterial for this wild species.
Compatibility and Cohabitation: Strictly peaceful. They bother no one, but are slow to feed. Excellent with Hatchetfish (Carnegiella), small tetras (Cardinals, Nematobrycon) or Dwarf Cichlids (Apistogramma cacatuoides).
Aquarium Breeding: Curious: they lay sticky eggs UNDER broad floating leaves, turning upside down to attach them (Corydoras style). The larvae will hide among the floating roots of the Pistia requiring rotifers.
Risks and Diseases: Open tank decay. "Diptails" jump instinctively to escape or hunt, but often do so even just if frightened by roommates. Strictly fitting lid with no gaps.
Geografische Herkunft und Verbreitung
Central Amazon Basin (Brazil, Peru, Colombia). Exclusively populate the surface of swamps ("Igapó") and slow streams (Igarapés), hiding under huge floating carpets (Salvinia, Pistia).
Ursprung
Amazonas, Orinoco und Guayana
Fischprofil
- Temperament
- Semi-aggressive
- They are timid, peaceful fish that spend their time quietly hovering. They are easily intimidated by boisterous tank mates and require a tranquil environment. In a peaceful species setup, they are incredibly serene and mesmerizing to watch.
- Diät
- Omnivore
- They are micro-predators that specialize in feeding on tiny surface-dwelling insects. In the aquarium, they will readily accept floating micro-pellets and crushed flakes. Live foods such as fruit flies and mosquito larvae are highly relished.
- Lebenserwartung
- 3-5 years
- Erwachsenengröße
- 5 cm
- Geschlechterverhältnis
- School
- Keeping a balanced group of both sexes encourages natural and fascinating behaviors. Males are slightly slimmer and more colorful, often engaging in harmless displays. A large school provides the best visual impact and social stability.
- Fütterungsfrequenz
- Twice daily
- Feed them small amounts two or three times daily to mimic natural foraging. Because they feed exclusively at the surface, ensure food floats long enough. Careful observation is needed to confirm all individuals are eating.
- Bioload
- Low
- The Brown Pencilfish, or Diptail, has a remarkably low bioload impact. Their diminutive size makes them perfect for smaller, densely planted aquariums. Excellent water quality must still be maintained despite their low waste output.
- Fluss
- Stagnant
- They require very gentle flow, reflecting their natural still-water swamp habitats. Strong currents will disrupt their unique oblique swimming posture and cause stress. Baffling the filter output is highly recommended to create a calm surface.
- Sprungrisiko
- Yes
- Given their strict surface-dwelling nature, they pose a very high jump risk. A tight-fitting lid with absolutely no gaps is essential for their safety. Floating plants can help create a natural barrier and reduce jumping tendencies.
- Reproduktion
- Oviparous
- Breeding is challenging and requires a dedicated setup with very soft water. They lay their eggs directly on the underside of broad aquatic leaves. Adults must be removed post-spawning as they will quickly consume the eggs.
- Kompatibilität & Tankkameraden
- Peaceful
- They are exceptionally peaceful and should only be kept with similarly gentle species. Small tetras, dwarf corydoras, and otocinclus make excellent, harmonious tank mates. Avoid housing them with fast, aggressive feeders that might outcompete them.
- Tankfüllstand
- Top
- They are obligate surface dwellers that rarely venture deeper into the tank. They are famous for hovering at an oblique, tail-down angle just below the surface. Floating vegetation is crucial to provide them with a sense of security.
Wissenschaftliche Modelle & Parameter
FishBase
Zugang zu den offiziellen wissenschaftlichen Daten der Art
FishBase v25.04Daten synchronisiert am: 15.06.2026
- Trophäenniveau
- 3,3 ± 0,4 se
- Belastbarkeit
- Mittel (1,4 - 4,4 Jahre)
- Phylogenetische Einzigartigkeit (PD50)
- 0.5
- Bayessche Längen-Gewichts-Beziehung
- a = 0.00759, b = 3.13
- AnfälligkeitGeringe Anfälligkeit (10 / 100)
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