Three-lined pencilfish
Nannostomus trifasciatus
A pencilfish with three distinct black longitudinal bands on a golden-red body — the largest and most classic of the genus. At up to 6 cm, it is noticeably more robust than nano cousins. Displays the characteristic Nannostomus nocturnal livery with dark spots appearing in the dark. Can be slightly territorial with conspecifics but remains peaceful in community — needs sufficient space to establish micro-territories. Ideal Amazonian blackwater biotope with tannins and dim lighting. Lid: jumper.
Temperatura da água
24 - 28 °C
Valor de pH
5.5 - 7
Tipo de água
Água doce
Nível do tanque
Superfície e meio
Tamanho adulto
5,5 cm
Volume mínimo do tanque
>= 55 L
Grupo mínimo
>= 6
GH
1 - 12 dGH
KH
1 - 6 dKH
TDS
25 - 240 ppm
Condutividade
39 - 375 uS/cm
Descrição da espécie
Geographical Origin and Habitat: Immense Amazonian range: from Peru, to Colombia, Brazil and Guyana (Rio Negro, Rio Ucayali). Lives in "Igapó", turbid but slow flood lakes.
Taxonomy and Morphology: Three-Lined Pencilfish (Nannostomus trifasciatus). Among the largest pencilfish (5-6 cm / 2-2.4 inches). Cylindrical torpedo profile. The "three-band" livery is the trait from which it takes its scientific name.
Social Behavior: Show-off. Males spend the day facing off shoulder to shoulder, vibrating vigorously to establish the school's hierarchy. Despite being combative, the brawls do not lead to injuries or deaths.
Coloration and Sexual Dimorphism: Three decisive horizontal black bands interspersed with vibrant gold stripes. The unique trait (which distinguishes it from the marginatus) are the incredible intense Blood Red spots splashed transversely between the gold and black bands. Males have a thicker red base on the dorsal, caudal, and anal. At night the three lines disappear in favor of 3 large oblique gray "stamps".
Cuidado, criação e companheiros de tanque
Aquarium Setup: Long tank (at least 80-100 cm / 32-40 inches for male duels). Needs ample horizontal space in mid-water combined with dense peripheral plant bushes. The shadows generated by tall stem plants (Cabomba) will calm them down.
Diet and Feeding: Lively micropredators. Will greedily eat small insects fallen in the water, daphnia, brine shrimp and will gladly accept flakes and excellent quality micro-granules scattered on the surface.
Water Quality: Very robust for a Nannostomus. Although they like acidic pH and amber water (ideal for red colors), they will thrive and live 5+ years even in normal soft conditioned tap water (Ph 7.0, GH 8).
Compatibility and Cohabitation: The emblem of the South American Community Aquarium. Robust and immovable, they coexist well with Dwarf Cichlids (Ramirezi, Apistogramma), Angelfish (provided the tetras are adults), Tetras (Cardinals, Rummy-nose) and Loricariids.
Aquarium Breeding: Males chase females up to the floating vegetation, scattering tiny sticky eggs. The brood will be relentlessly consumed by themselves if not placed in a sterile tank with an egg-saver net on the bottom.
Risks and Diseases: Misunderstood nocturnal fading. A fright or the nocturnal phase triggers camouflage (Fright pattern): the fish becomes pale white, the lines disappear and spots appear. The aquarist often believes it is dying or sick, but they recolor as soon as there is light.
Origem e distribuição geográfica
Immense Amazonian range: from Peru, to Colombia, Brazil and Guyana (Rio Negro, Rio Ucayali). Lives in "Igapó", turbid but slow flood lakes.
Origem
Amazônia, Orinoco e Guianas
Perfil de peixe
- Temperamento
- Semi-aggressive
- These pencilfish are highly peaceful but can be somewhat skittish in sparse environments. They must be kept in groups of at least six to feel confident and display natural behavior. In appropriate numbers, they will actively interact and explore their surroundings.
- Dieta
- Micro-predator
- Their natural diet consists primarily of small insects and tiny crustaceans. In a home aquarium, they will eagerly consume finely crushed flakes and suitably sized pellets. Supplementing their diet with live or frozen daphnia and cyclops brings out their best colors.
- Expectativa de vida
- 3-5 years
- Tamanho adulto
- 5.5 cm
- Proporção sexual
- Group
- Males are generally more colorful and have additional red markings compared to females. Keeping a ratio with more females than males reduces competitive stress. A balanced group minimizes territorial squabbles among males during spawning behavior.
- Frequência de alimentação
- Twice daily
- Due to their high energy levels and small stomachs, they require frequent, small meals. Providing food two to three times a day is ideal for their metabolism. Ensure that the food particles are small enough to fit into their tiny, upturned mouths.
- Carga biológica
- Low
- The Three-lined pencilfish carries a very light bioload, contributing little to the nitrogen cycle. They are small and highly active, but their waste production remains minimal. This characteristic is perfect for maintaining pristine water conditions in planted tanks.
- Fluxo
- Strong
- They originate from sluggish waters and therefore prefer a gentle to moderate current. Too much flow will force them to expend unnecessary energy and cause fatigue. Strategic placement of driftwood and plants can create calm resting areas.
- Risco de salto
- Yes
- These fish are notorious jumpers, especially during feeding or when frightened. A completely secure and tightly fitting aquarium hood is a strict requirement. Floating plants can also help deter them from leaping out of the water.
- Reprodução
- Oviparous
- Breeding Three-lined pencilfish can be tricky, demanding very soft water and dim lighting. They scatter their adhesive eggs among fine-leaved plants or spawning mops. The parents will eagerly eat their own eggs, so prompt removal of the adults is necessary.
- Compatibilidade e companheiros de tanque
- Peaceful
- This is a peaceful community fish that thrives alongside other gentle species. It is important to avoid housing them with fin-nippers or large, predatory fish. Excellent companions include small tetras, Corydoras, and peaceful dwarf cichlids.
- Nível do tanque
- Top/Middle
- They are predominantly top and mid-water dwellers in the aquarium. They can often be seen cruising near the surface looking for floating food particles. Including tall plants provides them with necessary cover in their preferred swimming zones.
Modelos e parâmetros científicos
FishBase
Acesso aos dados científicos oficiais da espécie
FishBase v25.04Dados sincronizados em: 15/06/2026
- Nível trófico
- 3,3 ± 0,39 se
- Unicidade filogenética (PD50)
- 0.5
- Relação bayesiana comprimento-peso
- a = 0.01023, b = 3.13
- VulnerabilidadeVulnerabilidade baixa (10 / 100)
Galeria de imagens
Imagens licenciadas vinculadas à espécie ou, quando marcadas, ao táxon representativo mais próximo.
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